One very handy, and cheap, computer accessory you should consider is a Flash USB drive. The devices, which are slightly larger than a matchbook, let you carry a hard drive in your pocket.
You can find these devices from a number of manufacturers with different price/memory combinations. I picked up a 64 MB drive for $29.99 (being a computer product, prices fell again almost immediately after I bought it), and you can also buy drives with 32, 128, and 256 MB and all the way up to 1 GB.
What are some uses for these drives? They can function as a "Nike Network" whenever you need to transfer files between non-networked computers: carrying files between home and work; or to a friend's house; or between laptops at a conference. Yes, floppy drives do the same thing, but how many MP3s can you fit on a floppy? Plus, more and more laptops are leaving off the floppy altogether. You can also burn a CD to transfer the files, too, but you sure can't carry one in your pocket, and these are much faster to operate.
It's not just size that matters here — ease of use is even more important. Once you pull off the cap and expose the USB connection, all you have to do is plug it in to a USB port on a Windows XP/2000/ME, Mac OS 9, or Linux 2.4 computer. Your computer will automatically recognize this as a new drive, and let you copy or paste files using any standard file management tool such as Windows Explorer. There's no need to load a driver onto the computer (unless you are using Windows 98SE). Mine worked right perfectly with a Windows XP desktop, an XP laptop, and with a Windows 2000 computer. When shopping, make sure that the drive you buy is compatible with your USB port (drives and ports will either by USB 1.1 or the faster USB 2.0).