Been looking into getting an external hard drive for backups and because I'd like to have my itunes library off the main hard drive as it always takes up loads of space, and had a couple of questions with regards to time machine.

I've read that you're supposed to use a hard drive for time machine and time machine only, is this right?

I'd like to get a drive that's big enough to back up my system and also be used as general storage, but am I better getting two - one for time machine and one for files?

I do a lot of recording with logic so I'd like to have something that I can record to, so was thinking firewire 800 is best for this (I have the 13" MacBook Pro)...

Any advice?