I highly suggest the 8500GT or 9400GT. CPU Playback can't match GPU playback in terms of smoothness. Over here in NZ we have Freeview HD h264 DVB-T, which is broadcast in 720p and 1080i. Plays back smooth as with GPU acceleration on all my computers, that is 8500GT, HD4850 and 9600GT. I use the PowerDVD8 codecs.
If you asked in the NZ thread about playing back HD (MPEG4 h264, not MPEG2) with that system you'd be told to get a graphics card.
If you asked in the NZ thread about playing back HD (MPEG4 h264, not MPEG2) with that system you'd be told to get a graphics card.