Gary at HD Guru found the most aggressive pricing at J&R, Costco, Fry'sand Vann's. He put together a list of like 23 deals, and even wrote up a guide to judging whether or not you should buy the new TV or last year's model, based on specs and expectations.
You can get a premium 46" Samsung LN46A650 with 120Hz for $1400 at Fry's (if link doesn't work, go here and search). It originally listed for around $2100, but Amazon is selling it for $1500, to give you an idea of how low this is.
There's a 52" Sony KDL52W4100 at J&R for $1550, down from $2200.
The best deals of all seem to be Panasonic plasmas, which is funny because, performance wise, that's where you can pay less for more TV to begin with. The winner here is Panasonic's TH50PZ85, a 50" 1080p plasma for $1300 at Fry's, and he said Costco carries it too for that price, though I don't see it. This deal is amazing not only because it's marked down $900 from $2200, but even Amazon is still listing it much higher, for $1700. Now all you need is money, right? That's the tricky part.