I have Samsung X30.
You can playback divx and upscale to 1080i but to be honest I barely see the difference compared with 480p and even with 720p.
It reads USB well, but displays JPEG in 480p only. Can play one jpeg or Mp3 but not both, other players can play mp3 while doing JPEG slideshows. It has optical input so if you have another DVD player or a laptop, then you can connect it so the samsung can decode the DD and DTS.
But the sound power is very good, I was blown away how loud (w/o distortion) can it go. VERY good HTIB, but fro music, I dont like the sound.
And for DVD playback, again you can barely see the difference regarding the upscaling.