5400RPM is fine. I have a 40 gig hard drive that's 5400RPM and all my songs and apps are on the drive. Works really well for storage and stuff like that...
BTW, junthin is right about compaqs. I have a 1ghz athlon, and what did they do? put a 40 gig 5400RPM maxtor in as the main drive. Needless to say I quickly got a 7200RPM drive 🙂