I rip my CDs to FLAC format (it's a lossless format that preserves the audio quality of the CD) using Exact Audio Copy: http://www.exactaudiocopy.de/
Then I use a program I made myself (FlacSquisher: http://sourceforge.net/projects/flacsquisher/ ) to convert the FLAC files to Ogg format (FlacSquisher can also convert to MP3s). I keep the FLACs on my desktop, and put the Oggs on my Sansa, which has Rockbox ( http://www.rockbox.org/ ) on it. Rockbox is a replacement operating system for portable media players, kind of like having Linux on it.
A few years ago I used to carry my entire CD collection in a giant CD wallet, but it got stolen when I was moving into my dorm, and since then I've ripped my CDs to FLAC format so that if I ever lose any other CDs, I'll still have perfect backup copies on my computer. As it is, I only have 160kbps MP3 rips of my old CDs, which is terrible because MP3s weren't designed to have smooth transitions between tracks, and I listen to tons of prog rock and classical music.
Check out Exact Audio Copy and FlacSquisher if you like having CD-quality music on your computer, and want to save space on your portable media player.