Inside I know it'll be released for the PC, doing the opposite would be a really really big let down to a huge part of the GTA community.
But I haven't thought about Vista exclusive, that's a little disappointing :/
Vista is pointless at the moment, and I believe it'll be as pointless in 08. So I wouldn't want to buy it.
I heard there's going to be an even newer Windows coming out in late 08 or 09 so yea, bla bla bla Carrying myself off here.