Recently I went ahead and built a nice pc rack rig with a Gigabyte EX58-UD5, I7 920, 6 gigs DDR3, two Nvidia double head card and I'm waiting for a Decklink HD extreme to arrive soon (3x19" LCD monitors and a 37" Lcd TV). I've installed a retail Snow Leopard rig. Everything works (including apple update) except my SonicCore Cards

I have spare (in hd caddies) systems : Win 7/32 & Win 7/64. This rig beeing used full time these days with video editing, It doesn't get used in windows at all.
I find the apple OS very pleasing to work with. Lots of little details (especially in snow leopard) makes me think of switching platform for the audio too.
At the moment my former rig is still 100% functionnal and installed (2x wide 19" lcd monitor). The Apple rig is connected via optical spdif (the motherboard's one) to the scope win xp sp 3 rig. I have a spare luna + 2 adat I/O bracket in this machine as well but no mac drivers for it yet. An Mbox mini 2 is installed so I can run the Protools 8.03 pre release (not doing so well at the moment...).
It sure would be great to have mac drivers for 10.6 one day for the SC cards, but I doubt it'll arrive anytime soon. So I'm using the SFP mode (yes...) and I might stay there. I'll be getting a digi 003R soon and I'll use the Minimax/C4T etc... in external instrument mode and I'll use a few instances of the nice SC reverbs in ext fx with protools and Nuendo on the mac (via the adat connection).
If it's too cumbersome, I still can come back to windows with a reboot/swap disk tray in a couple of minutes.
Ideal !
If you're into tweaking, coming from the pc world even gives you an advantage to mac only heads since it gives you the "cmd prompt ability". Let me explain. Building a Hackintosh rig implies some computer experience at a deeper level ; carefully choosing the components, finding the right kexts, the right method (Vanilla/patched distro or EFI/Extra... ?), tweaking the com.apple.boot.plist, the dstd table etc... Some cmd prompt syntax knowledge etc...
After you've gone through this, you can pretty much tweak/Modify/fix a real mac too. And that happens very fast trust me !
Here at work (we are an independent 3D, photography, print, film & music production company) there are lots of PCs (3D render farm) and macs (print, 2K video compositing and special fx with 8 core mac pro, kona hd card etc..., ).
In the last weeks, I've seen the expression of the guys coming in the studio to see the rig's construction progress going from "Yeah, dream on" to "Woaw it works !". Now it is "Can you help me out on this hardware mac issue I have ?" time ! I've realised most (even very high end specialist) mac users don't go that far in the os knowledge.
Since my studio is getting used in various tasks (audio and/or video work) and is used by inhouse and freelance technicians having a mac os rig is MANDATORY.
For the first time, I don't have to justify why I'm on Nuendo instead of Protools or why on Windows instead of the so called elitist Mac world. I've got both !!!

I don't know if it's the novelty factor, but the Mac os thing is growing on me lately ! help !!!

Bifop