Here comes the first 65w-TDP (Thermal Design Power) Quad-Core Phenom II X4 905e offered by AMD, featuring Socket AM3, Operating Frequency 2.5GHz, Hyper Transports 4000MHz, L2 Cache 4 x 512KB, L3 Cache 6MB, 45nm Manufacturing Technology, 64 bit System, Hyper-Transport and Virtualization Technology Support. Judging from its low TDP, it should fit in your list if you really want to have a Quad-Core processor for your HTPC.
But I would wait for a while for my next HTPC machine as Intel will be launching its Core i3 processor with GPU integrated inside and supports MPEG2, VC-1 and AVC (H.264) decoding and passthrough Dolby TrueHD and DTS-HD Master Audio and probably be available in Q4 this year! It's still not clear whether AMD would come up any solution for Dolby TrueHD and DTS-HD at the moment.