I use my laptop exclusively. I have an external keyboard hooked up to it and that’s all. I actually prefer the touchpad over a mouse and the 15" screen is large enough to look at without eyestrain. It’s fast enough to stream TV shows and movies from hulu.com and the various network websites. I don’t worry about using it for games. That’s what my XBox and PSP are for.
Been portable since 2003. I drive an iBook G4 running Leopard, the Mrs. a PismoBook running Tiger.
My oldest son has an iMac, but I think he misses uses the laptop a little.
When I had both a desktop and a laptop, I found that every time I installed/downloaded/bookmarked something on my laptop, I also wanted it on my desktop, and vice versa. And it got pretty annoying.
I know that there are programs out there that allow you sync the two machines up, but the programs don’t transfer everything. Plus, just the thought of using a program to do that was annoying.
There were times when I’d be using my laptop at home, with a perfectly good desktop to use, but out of necessity, I resorted to using my laptop only because it had files on it that my desktop didn’t have.
So, since I used my laptop more, I sold my desktop. Now all I have is a laptop, and things are much simpler.
Now that all but the cheapest laptops are more than powerful enough for day-to-day computing, there’s really no reason to buy a desktop anymore. Buy an external monitor, keyboard, and mouse to use at home, and just plug in your laptop. When you want to go somewhere, unplug it, and you have all your files with you. You can also use the laptop as a second screen, although in practice I just use mine to display pretty pictures.
Here is a picture of my desktop-equivalence setup at home. I have a similar configuration at work.
I use my Desktop for everything most of the time, the Laptop I use whenever I go away (like back to visit the family) and I want access to the stuff I tend to use on the Desktop, I also use my laptop in school or in classes, and sometimes keep my laptop in my (locked) locker for easy access there.
But I rarely use both at the same time, or my laptop at home if I have the PC.
This. When I’ve lived with my family/housemates, this was one of the best things about having a laptop. I always liked being able to sit in the kitchen/living room with family/friends and use my computer while still remaining sociable. It’s no fun being confinred to a bedroom/study while everybody else giggles and gossips in the other room.
IMO if you want the ultimate in performance and capacity, you need a desktop, but that’s probably OK because you also need a wired connection to get the full benefit.
Aside from that, there’s no reason you can’t use a notebook as your main computer, even if you spend nearly every day using it, over a couple of years. This one I have here is pushing two years old, and has been very heavily used for about one year. Although I so desperately need to increase the RAM and change out the hard drive to something bigger, that’s mainly because I’m running some very large programs on it, ones of which I had no inkling at the time I bought it. For run-of-the mill home users, thought, it would be fine.
Moreover, most laptops are a lot tougher than you would think. A few years ago, I inadvertently dropped my work notebook onto a polished stone floor, from a height of about four feet. Though I was horrified, and was sure that something was broken, it worked just fine.
3 PC’s and 2 laptops networked in the house and 2 PC’s in the garage. Wife like a laptop on the couch and I like a desktop. Both us some sort of mouse and I personally have to Track Balls on my 2 main desk tops. ( PC & LINUX) Printers and scanners on my XP PC and on the garage setup.
Laptops for travel of course…
Cooler pads for the laptops are the cat’s meow…
Separate battery back ups on everything including the router and modem, the LCD TV & DVR and cell phone booster and land line cordless phones.
Yeah, we got lousy electric out here at 40th & Plum… 
One of the pluses of my current job is that, since I’m supposed to stay in the same place during (most of) two years and it could be several more, it’s allowed me to buy a desktop again. I hadn’t had one in 7 years of bouncing around a couple continents.
When I use my laptop at home, I do it with a separate, full size keyboard and raised on an aluminum stand. The reason the stand is aluminum is because that way it doesn’t just put the laptop at a better height but cool it without using additional energy (do not try to give me a plastic base with fans or you may eat it). And I always use my own mouse.
I’m a bit baffled at all the replies suggesting the social benefits of laptops - “now YOU can join in the gossip and banter with your family and friends while working!” Maybe I’m just easily distracted, but whenever I need to do anything remotely important on a computer, I need silence and solitude. To me, the fact that my desktop computer is stashed permanently in a dark corner of our house is a key ingredient in making it work.
I’m considering getting a laptop to take my files with me to the Uni and elsewhere, but I have grave suspicions on the true usefulness of the machine (incl. ergonomics etc.).
ETA: I get most use external keyboards, stands, mouses etc. to make laptops more user-friendly. Does this mean I’d need to shell out an additional 500e to pimp my 600e laptop for comfy use?
I got my current keyboard, mouse and stand all in one day and they were more in the 100€ total.
Here is mine: