I've been looking at the LA40B650 TV recently, espcially as it has some interesting media playback features over DLNA and USB. Tried some samples out in a store with mixed results.

Original off air Freeview|HD TS Streams
 * 576i - Don't work
 * 720p - Work
 * 1080i - Work

MP4 files - work
MKV Files - work, but some seeking issues

The one issue I did discover is you have no aspect ratio options when playing back over USB. The only two options are "Fill" or "Original". Some of the MKV files were 4:3 or 2.1:1 aspect ratio.

Anyone here had a play with this set and various media formats?