I worked in home theater for 9 years. Avoid off brands. Vizio is ok, they use NEC panels for the most part. Not the best, but of the cheaper manufacturers they'll beat the piss out of Sanyo, Norcent, and whatever Taiwanese garbage WalMart is pushing the elderly these days.
My honest opinion would be to avoid LCD and get a 42" plasma... but everyone will scream "OMG THE BURN IN" and yeah, you could burn it in, but it's really tough to do with the phosphors they're using these days. Plasma will deliver deeper blacks, more vibrant colors, and really don't have any sort of "response time" or screen smear you get with LCD.
If you're dead-set on LCD, stick with Sharp or Toshiba. Avoid the Korean and Taiwanese panels, they're garbage. Vizio isn't bad, but for the same money you can get a Sharp.