WinDVD 7, on Windows XP Media Center Edition 2005. Update Rollup 2 is applied, but everything applies pre-UR2 anyway.
Using Australian Free-To-Air Digital TV via an Avermedia A16A.
Good de-interlacing, better than PureVideo
Excellent image quality
Supports HD without any noticeable problems so far
Doesn’t stress the CPU too much (Radeon 9550 @ 1360×768).
Few tweakable options available directly. I couldn’t find them, anyway.
Subtitles on DVDs can be iffy – where subtitles appear for only part of the movie, they often don’t display. If they don’t display, enabling the DVD’s in-built subtitles from the DVD menu, playing a little, then turning them off gets them working.
Sometimes can’t watch Live TV while it’s recording – you have to go via Recorded TV, and play the recording. Might not be a WinDVD thing, but it’s worth mentioning.
A WinDVD thing: Resuming Play speed after fast forward/rewind is flakey (skip works fine), and you often end up with a “can’t play the stream” decoder error. Just hit Stop and then Play.