I, like many others here bought a Mac Pro as a workstation for music production. Although, I built another beast of a watercooled rig for gaming, the Mac is happily at the heart of my recording studio and rarely gives me any problems.
Like some of the previous posters, I agree that Mac OS X is a fantastic OS and its no-nonsense approach coupled with rock solid stability increases workflow no end. I only now use Windows if I have to and to put it into perspective, I have a watercooled PC with the following specs:
ASUS P5K-E Wifi
Intel Core2Duo E8400 @ 4.40Ghz (487x9, 1.35v)
750GB Samsung Spinpoint F1
4GB OCZ Reaper 8500 @ 975
Radeon 4870X2
M-AUDIO Delta 66
This custom water-cooled PC takes 40 seconds to boot (Windows Vista Sp1 64 NEW format). LOL!
My 2 year old Mac Pro (early 2006 model @ 2.66Ghz) boots in 15 seconds!
Furthermore, Mac OS X aint like windows where you think its booted up but still chugging away doing something pointless. The Mac is TOTALLY booted up in that time - absolutely amazing! In my industry, time IS money. The less time I spend messing around with crappy software/hardware the better!
Tom