I have an Nvidia 9400gt in my purpose built HTPC, running win7 mc off an SSD & an Asus P5G41T-MLX motherboard.
It's silent with a heatsink, full height & has HDMI out. Possibly a bit long in the tooth, but perfect for my HTPC set up. The only concern I have is with the spacing of the expansion slots, the heatsink does sit millimetres from the next card, but touch wood, three years in situ, nothing's gone bang yet.