Vista 64 now supports Win7 64 Bit is what I see. Cause I know that Win7 64 Bit works. I use it myself. I can see dropping support fo XP X64, since that coding is based off of a server based OS. I would say that you could just use the Win7 64 Bit version in Vista 64 Bit and it will work fine. Wont be the case for XP. But as I said previously, they use 32 Bit browsers. So there is no way that they could drop support, they just added it to another version. If not IE, Firefox, Opera, Safari, and the rest would not have Flash support in Vista 64 Bit since they are all 32 Bit Browsers. There is only 2 64 Bit Browsers to date. IE 64 Bit that comes with 64 Bit windows and Firefox Nightly 64 Bit. So Adobe is just condensing the amount of versions listed.