korell: You'd think so, and for many cases it is the case, but not always. Have a read around here on the forums and you'll find a fair few cases where games are working on Vista but not Windows 7.
Oh, and Windows 7 has DirectX 9, 10 and 11, whilst Vista still only has DirectX 9 and 10 (you can get 11 installed but it has not been officially released for Vista yet).
True, but unlike the Halo 2 fiasco (which was hacked to run under 9.0c), there are no games that make DirectX11 mandatory. Heck, outside of Halo 2, I can't even think of any games that require DirectX10. Batman Arkham Asylum, Street Fighter IV, Resident Evil 5, Demigod etc, all allow for the use of DirectX9.0c, which was released during the time of WindowsXP.
But I do recognize that there are likely going to be some issues with Windows 7. One particular issue I have, is running games over HDMI, that do not have resolution settings that match my maximum native output (1366x768) on my laptop. So anything below that, or below a widescreen resolution, will not run on my HDTV. This is only an issue with Windows 7, but Windows Vista (more appropriately ATI CCC, under Windows Vista) would force scaling, regardless of resolution. But generally speaking, Windows 7 should be fine.
