I've been using TMPGEnc Express to convert any videos I want to watch on my n810 to DivX 4.12 @ 400x240/23.976 FPS and MP3 128KB/48kHz. They look and sound great even in the Maemo player.

Since HD space is so not an issue these days I just have a directory on my NAS for my IT videos. They also end up a bit smaller than the originals so when I go on the road I can bring a bit more with me on my flash cards.