Congrats! Just don't get carried away with your mp3 collection like I have MP3s saved my cd collection though. When my cd case got stolen I had backed up quite a few of them to mp3 so I wasnt out a whole heck of a lot (still irritating to loose my original copies though)

A bit of warning though, some cds have copyright protection built in and won't let you copy them to your computer/mp3 player or if they do the files sound really bad. What sound formats does your mp3 player deal with? I had one that played wav files and wma (Windows media player format) files as well as mp3s so I could usually get around the copyright thing by just copying the files to wma format as the cd will let you do that most of the time.