Re: Best TV for XBox 360 & Ps3
the PQ of UT50 and ST50 are most probably not too different, and almost equivalent. the ST50 has got a better filter, which translates to a bit of loss in brightness. so i think you should go with UT50. i hope you don't have windows in front of your TV-placement area? if you do, then please cover them with drapes. and if not, make sure you control the lighting in your hall.
the distance is almost perfect for viewing movies/playing games on a 50 incher.
the dealer probably is telling the cost including some freebies too (?!). in that price, you could easily get 42ST50 IMO. infibeam is a trustworthy site (for small items), but it has now become like tradus, where sellers list their items. i think for small items, buying online is good, but for such a big thing as a TV, you should refrain buying online. moreover, its been garnering some negative feedback too since some time. for books and cheaper stuff, its good. but even if you get this TV for a little more costly locally, you should buy it from that local store instead from infibeam or other sites. i'll suggest to look for more local-options/dealers and haggle. let us know where you stay at. may be we could let you know if there's a better deal available anywhere near your area. chennai has some pretty good deals on panasonic TVs. but don't know where are you located.
also, do check a few samsung plasma sets, with showroom lights on and off.
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but i say again - if your gaming-hours are going to be much more than movie-watching hours, buy an LED-LCD TV (better for gaming & static content)!

LG's 42LM6410 is a good one, with some features included for gaming. LG also reportedly has a good customer-service.