If you get a Mac, the system will work like a charm and you'll be satisfied. However, as mentioned above, your options are severely limited. One good software package. One good soundcard. Welcome to "Why the Mac is More Stable than the PC 101"
If you get a PC, you WILL have headaches. There will be days where you're yankin your hair out left & right. BUT, suddenly you have SO many options. Soundcards up the yin-yang...multitracking software everywhere from $35 to $350. Also, you WILL save money building a PC for recording only. The PC itself can be built for $600-$700 with a small monitor and no soundcard.
You have to decide what's right for you based on your computer knowledge and budget. Look up "Pro Tools" and start from there...and avoid iMac like the plague.
(BTW, I am a PC person big time. But if I was rich and buying a machine that was for recording only...and I promised myself to never play with it...I'd probably get a Mac)
Slackmaster 2000