AMD says about Linux Avivo support even for AGP cards
And what about NVidia? for me new PC is not a priority, cause it seems, that buying X1950 card will be enough to watch HD movies with hardware offload. Buying new NV card supporting VDPAU means for me new motherboard and CPU - and then I wouldn't need hardware offload. You should really think about partial CPU offload (as in AMD implementation) even forcing community to write software modules. OC if you don't want to loose users - as your cards are kinda expensive in comparision with AMD ones. I've seen mentioned above card working smoothly with Linux. 50 Euros is nothing for me...