I agree with Bonuskun. The only thing that'll prevent SNK Neo-Geo (or whatever they're called now) from going under AGAIN is to make money. DC's sold like SPAM at a mosque as far as Japan is concerned, so I'd rather see it go to the PS2, Gamecube or Xbox. Heck, if the GBA could handle it, it should go there too.
I'm pretty anti-MS in many regards, and I'm not thrilled with the PS2's muddied design (they're trying to do too many things with their system, like 3DO did). I can't say I'm thrilled with the Gamecube's controller for fighters, either. However, they're all good systems (technically speaking), and should be able to handle KOF adequately. SNK needs to make money, not lose it.
Personally, I'll follow the games to the system they go to. KOF would be a deciding factor for me between an Xbox or PS2 (assuming the VF4.1 leak from Sega Europe was more than just a rumor). Follow the games, don't bother being loyal to any system...not a PS2, not a GC, not an Xbox, not even an MVS. If the games aren't there, don't bother. If you've got the MVS and can swing the outrageous price of the cart, cool, invite me over, I'll bring a pizza. I can only afford $50 at most for a game, so the $300-400 price tag a new cart would cost me is better put towards a system, extra controller, and a game.
And I'll make sure it's an SNK game if available!
(note: Don't get the wrong idea about the MVS comment...I had an AES back during 92-96, and a Neo CD during 96-97...currently the proud owner of an anthricite Neo Geo Pocket Color...I've been an avid SNK supporter ever since I first put a token into an MVS 4slot with Sengoku and King of the Monsters! I want SNK to succeed and prosper...I lament the death of my DC, but am glad Sega is still around to make games...)