I have got one 50" HD ready plasma LG and one 40" Samnsung LCD full HD. Both are equally good.
I would suggest to go for one with direct input from USB. Some models do have usb input but they can only play music or show pics. Newer models comes with full movie support on different formats.
Also LG comes with built in hard disk for recording.
If you do the research, there are only two or three companies making screens for all the suppliers so quality of big names will not have much of difference.
I hope I have confused you enough.