To echo BB, I have a 37 inch Sharp Aquos 720p LCD and it's been nothing but great. I've hooked my netbook up to it a few times and watched stuff on Hulu and ABC.com very nicely. Just need a bluetooth mouse so I can change stuff without getting up! LCDs tend to have a problem with blacks, but the Sharp has a setting where it stabilizes the in and out fading of the darks and blacks, and it's worked very nicely.
FWIW, If you're putting new TV in a dark room, I'd go plasma. If the room will have natural light, or you'll hook it up to a PC from time to time, go LCD. And if you do go LCD, make sure to get at least 120Hz refresh rate. I'm not up to speed on LEDs just yet, but from what I see, they are very nice looking.
Plasma route, take Matty's advice and go Panasonic. LCD route, the Samsungs have been highly rated.
As far as where to buy said TV, if you don't mind ordering online, I'd suggest Newegg and Crutchfield.
And if you do buy a mounting bracket and any A/V cables, go to
http://www.monoprice.com.