Glad you got the video driver issue resolved. When using the x64 version I take the same approach as when Win NT 4.0 came out and required a driver explicitly written for the OS, make sure that the driver says it works on vista x64 systems. Even when running XP x64 I ran into the same problems, though Vista is a bit more demanding when it comes to drivers (and hardware resouces).
Though it sucks having to spend $20 bucks twice, for the amount of hassle and frustration for those of us using Vista x64 the D2D is the quickest solution (even though you're buying the same game twice, since its a great game I don't mind too much). Just install from the dowloaded files, install GWX and you're in business.
