Are you upgrading your hardware as well?
IIRC, MS provide a "Vista ready" testing kit, try that perhaps.

Is there anything "new" in vista which is a "must have" for you?

I have a new rig , it was 2 months old. My friends told me that vista has DX11 while XP has DX10 , DX 11 is better on gaming. I think it is not "must" but I'm just curious about vista and i wanna try it. Thanks for the info.

hi asameh99, try to check your hardware and software compatability if it will work with vista.... some programs may not work with vista.. so check carefully whether you're ready for a change...or you can dual boot your sysytem so you can still have XP..

There's no DirectX11 yet.!
Vista use DirectX10, while XP is 9.0 - 9.25c..something like that.

If you plan to upgrade and wish to do with DirectX10 on Vista..check out your Video card whether it supports support or not. Example, Nvidia 8800GT, GTS..& the 9 series are compatible with DirectX10.

Latest gaming right now requires high performance PC. You should have at least Core2 Duo 2.66 to Quad core 3.0Ghz to play..included the latest video card which I have mentioned above.

Thanks.

Most games make little to no use of multi-core processors, so having the higher clock speed is better than upgrading from a dual-quad core computing. Vista is *very* resource intensive, but personally, I like a lot of the features it gives. I wouldn't use it on my gaming PC, because the driver support is still a little flaky, but for personal use, it's great.

Little typo there I'm guessing, Vista has DX10, XP has DX9

Go for vista. XP will be dead soon.

Vista has better hardware support, looks nicer, and once you get past the learning curve, its pretty handy.

If you are going to buy one, get vista because as Jbennet said XP is going to be left completely unsupported soon enough. Vista has started to grow out of it's quirks and bugs now so soon it will be good. But check your hardware first... but if it is a new computer it should be fine. What do you have on it now?