mac and logic.
OSX uses plug-ins in Audio Unit format. Not vst. You can buy a program that will convert vst to AU.
I have had no problem finding music software for mac and OSX (except of course if you want fruity or sound forge)...
hope this helps...
I use a G4 powerbook (867mhz, 768mgRAM, it screems) with Logic6pro, reason, and recycle. I have reaktor4, but I've had a shit hard time using it with Logic because it's a CPU monster, and it dosen't always play the notes you program!
mac is expensive, but wicked fast and stable for music production.
cheers