I need to begin considering getting a new video card since mine isn't holding up too well with modern games (Spore is the breaking point, as apparently I don't have Pixel Shader 2.0). The video card itself is still an old type PCI card.

My motherboard is ready for upgrades, but my operating system is still Windows XP. I certainly plan to upgrade that someday so I handle yet newer games, but not too soon.

Now I know XP does not support DirectX10, but I want to get myself a DirectX 10 video card for when I finally do upgrade. Can I get that video card now while I still have Windows XP? Would the video card itself work just fine? Or will I need to delay getting such a card until I upgrade my OS?

Then on the side, when I do get a video card, should I get one marketed as DirectX 10.1, or do the DirectX 10 cards handle DirectX 10.1 after updating them? Or should I wait yet further for the upcoming DirectX 11 and Windows 7?

Your computer will be able to run the card fully in DX9 mode. My 8800GTX is a DX10 card but I'll never use Vista except for a dual boot when I get around to playing better games that should come out..

ATi is the only brand that makes cards compatible with DX 10.1 currently so maybe going with them is better but DX 11 will be many many years away.

Any DX10 card such as the 8800/9800GT will serve you fine for a LONG time, so don't worry.

Yes, dx10 cards work with XP, just at DX9.