For better post-sales support, those are the two you should start with, besides overall good PQ. Prices are good now too, I see.
That said, I would suggest you check out the dedicated model-specific forums @ AVS too. They have great tidbits from owners/enthusiasts besides the very basics that are usually covered here.
My girlfriend and her sister recently moved into a new apartment and I offered to buy them a television. I was initially going for something in the ballpark of 43", but I'm thinking I'll probably move into the 48" to 50" range instead.
The "Smart" TV stuff isn't terribly important since there's dozens upon dozens of gadgets I can plug in that are capable of Netflix playback, so that's not a selling point.
Ideally I'd like to stay under $500.
These are the four I'm deciding between at the moment:
50" Sharp LC-50LB370U - $429.99
49" LG 49LF5500 - $449.99
48" Samsung UN48J5000AFXZA- $479.99
48" Vizio E48-C2 - $479.99
Thoughts on any of them?

Chowhound
Comic Vine
GameFAQs
GameSpot
Giant Bomb
TechRepublic