recommend cheap hardware assist HD decode x.264 video card?

[bluenote]

Hey guys

I'm considering upgrading the video card in my P4 3.2 pci-e box, to play HD content, in various formats, -- I assume x.264 or xvid will be most common, but really I would like as much compatibility as possible.

Now I've done a little reading about CUDA and avivo, but I'm really not getting that warm fuzzy feeling about picking a card thats going to work in all situations and for all purposes for a cheap price. I've seen the ati 4350? recommended a few times.

Basically, it seems to me that you could shoot yourself in the foot not making sure that all of your components are going to support all of the formats you want. Am I wrong? Is it as easy as picking a recent-generation video card of either brand and slapping it in and then figuring out decoders that will take advantage of the hardware acceleration? I also find it confusing that retailers dont seem to list this compatibility (avivo, or purevideo? or purevideo HD? or CUDA or whatever else???)

Can somebody spare a couple minutes to run this stuff down for me?

thanks

Cory