well the picture quality is only going to be noticably different if you are playing HD programs.
if you're watching sport then a high frame rate would be good, look for 100 or 200MHZ i think it is
for Blu-ray to be played at its best then a full HD 1920 x 1080 would be best.
HDMI cables are best for connecting other equipment, rather than scart, so try and get a TV with a few of each.
Ive got a JVC 42" lcd and for day to day stuff its good, but is really good when playing Blu ray