Cnet (if you're not familiar with them) IMHO is the best online news/ review source for electronics. They do an extensive buyers guide every so often and review tvs as soon as they come out.
If you go to Best Buy be weary of the sales people. They pretty much suck. I pay no attention to them unless I have a store specific question about a product. They have told me things like, "you can get a better picture with a better HDMI cable." I know damn well that all cables are pretty much the same save for construction, if they're rated for in wall use and if they're shielded for video use. The tvs there are professionally calibrated too. They aren't going to look like that in your place. They can calibrate yours to look close for like $250 though. I go there and look then buy from Amazon or something.
Amazon is pretty good if you find something you want. They price match including up to a few weeks after you bought it (it might be if they offer it lower). They will deliver your TV for free above a certain size and price though. By deliver I mean two guys from a shipping company carry it in, unbox it, put the stand on, verify it works and put it on your media stand and take the box/ trash with them. Also on Amazon, when I bought my Samsung they gave me 6% of the TV cost in site credit for future use (about $140), a free year of prime ($80 value), a week later I got $100 back because they lowered the price, and best of all...no tax.
Stay away from 4K. There is little content available and is still 1 or 2 years away from being readily available. Plus, HDMI 2.0 is really unproven technology (2.0 is hardware, not a cable,like a store sales person tried to tell me). Many networks still only broadcast in 720p too. All that other stuff about tru motion, contrast ratio and whatever else is complete non-sense. Really just get 1080p and probably 120hz refresh. Some programs don't even refresh that fast, so 60hz will work to. The TV can't refresh what isn't there to refresh.
I had a Vizio m-series. It was ok but had no features other than the smart apps. They use Yahoo! for the app provider which stinks. Picture was decent if those two things are all you care about.
I currently have a 65" Samsung 7150 series. A number of outlets called it the best HD TV of 2014. They change the model number every year, so it's available with an updated version (I think the 6700 series). It's a smart 3D. It has features including web browser, wifi direct (TV is a router), split screen(watch two sources at the same time), screen mirroring and reverse screen mirroring, ARC, and a some other things. You can still buy this model for about $1500 now. Samsung tvs in general I like, but some are pricey depending on the features.
I also have an LG 55". I think it's a LF6100 series. It's not as nice as the Samsung but does most of the same stuff minus the 3D and split screen options. It does have a good App Store. The search feature is awesome. If I can search for a show or movie and if it finds it, it will tell me where it's being shown (Netflix, prime or even on an app I don't have). I paid $600 for it at Best Buy last month. It sells for $699 now and $629 on Amazon; both will price match. It might be cheaper elsewhere, and there's always the option of a 60" in the same model.
I've seen Sony and know they are also pretty good but know little about them and the features. They are known for their life like screens though. You probably couldn't go wrong with this brand either.
I would stay away from everything else. Sharp may be worth a look, but I don't know. So I hope this helps. I am also moderately knowledgable if you have any questions.