False: Mac are the only computer that can do [insert anything]
Now someone might have misled you, most serious audio jobs are done on PC. They offer way more at small prices and are easy to upgrade in a studio, Macs make it easy to make music because it comes with garage band but thats it! What I suggest you is a "audio interface" such as the "Fast Track Pro" or something similar, it's kinda like an external sound card with midi In/Out, multiple Inputs (guitar jack, Mics etc...) and output (s/pdif etc...). It will land you in a zero latency zone (no delays). Theses things are usually USB and make it so easy to record and do most audio work on a computer. From then, you can use software such as fruity loops, Pro tools, Cubase, Ableton's Live, sound forge, acid, soundbooth, audition or even microsoft's recorder.
I have an amateur studio and know a lot of people who does, nobody has MACs. Most PCs can be opened and played with without voiding the warranty which is useful when changing fans to make it more silent.
Hope this helps, but know that a computer is a computer and a PC will do the job just fine AND way cheaper. Just make sure you buy an interface to plug Midi since it's not really standard anymore!