I use
VLC, Flex Player and PlayerXtreme
Mostly i use flex player
Supported video quality:
Up to HD quality (1280 x 720 pixels) for QuickTime media files (mp4, mov, m4v)
Up to DV quality (720 x 576 pixels) for other media files (avi, divx, xvid, vob, …)
Supported file formats:
AVI, DivX, Xvid, VOB, MP4, MOV (plus many more)