More then enough for mp3's for sure.
As for recordings, I would think that 451MHz would do, but to make certain, I would suggest that you for instance download the demo version of Powertracks Pro 9. This program will record midi and/or wav files and mix them, add effects, etc. If that works well, I guess anything would. http://www.pgmusic.com/ptdemo.htm
As for the HD, 10Gig minus one or two operating systems and some programs is going to cut it somewhat short for keeping audio recordings as WAV's. Convert them to mp3's as soon as possible. Midi files are short enough, no space problems there.
Have a nice weekend,