I have 4, my 5 year old home built that still works great, 2 cheapos from Sam’s Club and my new laptop. All are hooked up to my network and get access the internet. I finally got one of my 3 printers hooked up to the network so I can print from any computer. I just picked up a 1 TB remote hard drive, I am going to collect a much of the stuff off the 3 desktops so I have it all for a backup.
Three on the wall, XP PRO
Two laptops on the same network, XP PRO
Two in the garage working but not on the net. W-98se and XP Home.
The XP Home machine is a ‘give away’ to the next little kid I find who’s parents can’t afford one for them. I have given away 4-5 over the last few years.
Stash of parts to fix what others think is not worth fixing… 
Lets see
1 Server (dell dimension desktop)
1 general use desktop
1 music studio desktop
3 laptops (mine, my wifes, my daughters)
My son wants a netbook, and I plan to build a media center this year.
I also have a spare server for failures. And we gave a PC away to a friend.
Si
With me, it really gets to a question of ‘what do you consider a computer’ since I have so many portable electronic devices, most of which are computer-like. Going by the examples I see here, though, the answer would be three. Desktop tower, full-sized laptop, eeepc.
mrAru has a work issued laptop, and I have 2 laptops in which one mainly gets used by mrAru for gaming, and the other I use for work and everything else. We have a reasonably new desktop that crrently isnt being used because we have no dedicated office space for it yet. I have a mostly dead laptop that i have a replacement tft and motherboard but havent gotten around to rebuilding. @ more random old unused computers we havent bothered tossing out, 2 working amigas [1 500 and 1 1000, with assorted software] and a univac 1616 with no OS. It came off a submarine. We originally bought it to play a practical joke with but we never managed to get it set up to do it but we can hope to do so eventually=)
We each have a work issued laptop but I don’t think they count. So three, each of us has a macbook and there’s a mac mini that is the HTPC and file server rolled into one.
Not counting the carcasses in the closet…got to throw those out.
I have four, two are in active use, two are there just because I can’t see throwing out perfectly functional hardware
the two that are in active use are;
MacBook 1.83 GHz with upgraded 250 GB HDD, 2 GB RAM, and SuperDrive, this machine was cobbled together from two dead MacBooks
PowerMac G4 Mirrror Drive Doors, 1.25GHz, 1.5GB, 2 160GB RAID drive running 10.5.6, 120 GB games/misc drive running 10.4.2, and a 250GB Time Machine drive, dual SuperDrives, ATI Radeon 9800 Vidcard
the two “just because” machines are;
PowerBook G4 1GHz with 768 MB RAM, 60 GB hard drive, and Combo drive
iMac G4 800 17" with 768 MB RAM and 160 GB HDD, my OS 9 gamebox (Carmageddon 2, etc…) also built from scavenged parts
5 immediately available, including the very old one I use for Wing Commander, and bits for several more.
Zero.
Posting from work.
Lessee, inventory is down at the moment… There’s my laptop, Himself’s desktop and the desktop that runs the entertainment center/media server–these are all networked. Then there’s the quad-Xeon server that runs but sounds like a jet engine warming up so until we have a closet or something to put it in to muffle the noise it’ll probably remain a printer stand. One laptop, one desktop and a PS3 in for repair/rebuild. Ask again on Saturday and we’ll probably be up by a few since we have a laptop and a couple desktops coming in for rebuilds. We did have another laptop around but I gave it to my daughter. Oops, waitaminute, I just checked and yup, there’s an old Toshiba Satellite hiding in the shelves over by Himself’s desk–pretty sure it works but it’s running something retarded like Win2K and I could probably draw the desktop faster with colored pencils than to rely on the refresh rate on that thing. No idea where the hell it came from, either!
A while ago I put my foot down and insisted that all the old cases and parts that no longer worked or were so criminally outdated that they might as well be nonfunctional be recycled and a bigass load went out, to my great relief.
Yeah, we’re computer people too. 
ETA: Oops, forgot the two Windows Mobile 6 smartphones!
If you only count active computers, our house has eight:
(2) MacBook laptops
(1) PowerBook 12" laptop (my wife’s dedicated streaming-TV machine)
(1) G3 “Pismo” Laptop, used as our kitchen computer / guest machine
(1) G4 Mac Mini (my wife’s office machine / DVR)
(1) Intel Mac Mini (dedicated home theater system)
(1) G5 Quad (my desktop machine)
(1) Thinkpad (my dedicated microcontroller programmer)
If you count machines that work, but aren’t currently active (mostly kept for legacy purposes), I can think of at least another 6.
Yikes!
Three adults in the house…eleven and a half computers
One Powerbook
One iMac desktop
One WinXP laptop dedicated to running embroidery software
One WinXP box
One virtual WinXP machine (Parallels on the iMac)
A one-terabyte file server
A media server
Four dead PCs…
… two dead laptops (One proudly proclaims Made for Windows 98) and one dead and semi-gutted tower PC. IIRC, it’s an overclocked 2.6 GHz Pentium that just needs a hard drive to be usable. In a closet somewhere, I have an ancient Compaq luggable. Doesn’t boot and I’ve not bothered investigating if it’s only got floppies or the hard drive is borked. In the garage, there’s one of those micro desktops that was destined to become a file server, but it’ll more likely be destined for e-cycling if I ever find it as I think it’s been stripped for parts.
Interestingly, our housemate (the owner of the XP box) is completely frustrated with Windows and viruses and is thinking seriously of ditching it and getting a Mac.
I’m also pondering finding a cheap used Powerbook or MacBook or even one of those little Eee laptops for travel.
Oh yeah, the half-computer is my work PC when I telecommute. I’ve got its docking station and multiple monitors set up on the desk, so there’s always some physical presence.
Between the two of us we currently have five computers at home: We both run virtually identical 20" iMacs on a daily basis (**featherlou’s **actually has more RAM). She still has her old semi-working PC kicking around and I have my old iMac and Mac Performa in my office (both still run just fine and I fire 'em up every few months to to check how they’re doing). I frequently also have my work laptop with me – an HP running Vista which makes me wish very hurtful things on Bill Gates on almost a daily basis.
I gave up my Commodore Amiga 500 when we moved to our current home. Damn, that was difficult for me to do – I hate to part with something that still works, even if it is woefully obsolete. It still had some of the coolest games ever invented and much better graphics than one might expect from a machine with a whopping 1MB of RAM.
2 adults.
We’re actually down to 4 right now.
1 main/gaming desktop each
1 laptop
1 old desktop used for holding music and pictures.
Before we moved last spring, we had another desktop that barely hobbled around, and probably 5 carcasses.
We tend to build new machines every 3-5 years. The old ones usually aren’t totally dead, but outdated enough that it’s not worth rebuilding them.
A desktop with XP, updated with new hardware summer 2007. Used for gaming and surfing and paying bills.
A laptop with XP mostly just surfing and simple games.
An old E-Machine in a closet upstairs, I think it’s a 500MHz or so machine with XP.
Also a PS3 and a couple Tivos, they’re technically computers.
Between the 2 of us…
3 laptops
1 desktop
I’ve got a brand new 20" 2.4GHz iMac, and a brand new 1.6GHz eMachines PC running XP. In the closet I have a PowerMac G4 with a bad hard drive. I bought the PC as a quick, cheap fill-in machine after the G4 died so I could continue to get my Internet fix while I arranged to get the iMac (I have bad credit and no credit card, so I had to get my mom & stepdad to order the iMac with their credit card, and I’m paying them back).
I’m going to attempt to resurrect the G4, and if I’m successful I’m going to give it to my older, [mostly]-computer-illiterate roommate to take the place of his aging Win98 PC that has been giving him much trouble lately.
Depending on ones definition of computer:
Early '08 Macbook Pro (basically a desktop/media storage encoder/server these days)
Late '08 Macbook Air (my “around the house and travel” machine)
Girlfriend uses my old Dell XPS laptop
AppleTV
Iphone 3G
I have five computers. All desktops, all up and running.
My main PC, a Home Theater PC connected to the TV in the living room, a 500GB file server, a Linux system that I play around with every once in a while, and an ancient Pentium 200 that serves as my router. Plus a couple of old PCs that may or may not be functional, and a bunch of spare parts.
Yeah, I tend to find a use for my old computers instead of getting rid of them…
Two new and/or recently upgraded machines (Vista and XP), two gathering dust but still functional (XP on both). Maybe three if you count the old Mac Quadra in the closet, but I have no idea if it still works. All of those are desktops. There are also two old laptops around the house, one which is just too ancient to use, and the other which is only somewhat old but needs the hard drive reformatted. And my wife just ordered a brand new Eee PC (or whatever they’re called) last night.
There are two of us in the house. It used to be a lot worse until my wife forced me to take all the old desktops I had stored for parts to one of the E-Waste dropoff points a while back.