Target, Walmart,
Amazon. Well, Wal-Mart last, because they don't typically ship the super special priced ones. Target and Wal-Mart usually offer two day shipping, and Amazon does it you're a Prime member. If you're not, and haven't been for a while, you should be able to get a seven day free trial.
Thanks to the recommendations of great, helpful people on the budget board, I bought a 43" TCL television earlier this year. Decent price, good quality except the sound - which a helpful Best Buy rep explained is because the speakers don't face outward.