So, a friend of mine is building me a new computer. Now, on the one I have now, I store a -lot- of media, and emails, and obviously my bookmarks on firefox, etc. I want to transfer as much as humanly possible from one to the other, but I’m not real sure what’s the quickest / most reliable way to do this. I could burn CD’s full of data (and it’d be a -lot- of CD’s), or I could … I dunno… Purchase a big USB drive? It’d have to be pretty huge, too. Or are there better ways? Keep in mind I’m largely computer-illiterate (-especially- when it comes to hardware), so, if you could, keep the answers / opinions single-syllable and appropriate to a Luddite. 
Thanks!
You don’t need any drives or CDs - why introduce a middle man? just connect them directly to each other via USB cable. It would be even faster with USB 3.0, but even if your new rig has it I seriously doubt your old one does.
The least technical and most straight forward approach is to use an external hard disk drive. There are lots of different models and capacities at virtually every office supply and electronics places. Even Costco has them.
The manual that comes with it will tell you how to hook it up and if you have any problems, you know where to post your questions. 
Basically the drive will come with a USB cable. One end goes into the external drive’s case. The other goes into a USB port on your computer. There’s a little more to do after that, but not much.
However if you don’t already have an external drive, prices are still very high if you want to buy one right now. If you could tell us how much data we’re talking about, that would be useful information.
If you have a home network, and you probably do if you have a broad band connection, then you probably have a rough idea of how to connect to the router/modem that you got when your internet service was hooked up - either cable or DSL. But I won’t go into that right now.
One caveat here is that I’m assuming that you are ONLY interested in moving data and that you do NOT want to try to transplant the entire operating system from one physical disk to another. That too is doable but a bit more involved. There are free utilities like VMWare’s Converter that will clone your current boot drive and create a virtual disk, but I’m going to skip over that for the moment too.
What are you planning to do with the old PC? If it’s just going to be relegated to doorstop status, get your friend to pull the old hard drive and have him install it in the new computer as a secondary drive.
Hodge’s answer is the best one.
Even if you are going to be needing that hard drive back in the old computer, you can still hook it up to the new one, transfer the data, and put it back in the old computer.
This. And even if you want to keep your old PC in working order, and your friend is willing, you can do it temporarily to copy the files over to the new drive, and then put it back.
That failing, I use a WD Passport external drive for backup and transfers. They come in 500GB models you can get for less than $100 on good days (and I think you can get as big as 1TB with these). If you have a lot of media, having one of these for backup is a good idea anyway.
If you’re able to hook both machines up to your network at the same time, you can copy data across the network connection pretty easily. If your router or hub is only 100Mbit it’s not going to be the fastest in the world, but it’s simple and free.
All right, seems (from what people have said) that this’ll be pretty simple, albeit a little time consuming. Thanks a lot for the info / advice, guys!
Quickest way to transfer the data would be to connect the old hard drive to the new PC.
Let’s say you don’t want to take the hard drive out of your current PC. (If you don’t mind doing so, then what Hodge said.) Just network the two PCs - connect them with a USB cable, or connect them both to your modem, and follow the instructions that Windows 7 (I presume that’s the new comp’s OS) has for networking them.
Once they’re networked, just drag and drop from the old comp to the new comp. Then either leave them networked, or not, as you see fit.
What I’m kind of getting from your OP is that you currently don’t have a hard-drive based backup of your system or data. Because if you did, then this wouldn’t be an issue. So this means that at the very least, you want to keep your old hard drive around (and, if you want to be disaster resistant, not in the same physical location as your new PC).
You can either temporarily install the old hard drive in the new PC or buy a hard drive docking station or external case for the new one.
Option 1: As others have noted, if your friend is smart enough to be building you a computer, he/she is smart enough to know how to put your old drive in and copy data from it – or leave it as an extra drive. Note that some of your programs may need to be re-installed in order to work properly. If you just need the data then you can skip re-installing the applications that made the data. This might require purchase of a PATA–>SATA conversion connector. They’re cheap.
Option 2: If your friend is geeky enough to be building you a computer he/she probably has access to a router or switch; you can connect the two computers to the cluster device and transfer data over the mini-network from the old drive to the new one. You might have to borrow the equipment, but you wouldn’t need to keep it.
—G!
One, Zero, Zero
One, Zero, Zero
One – SOS
. --RUSH
. The Body Electric
. Grace Under Pressure