Here are some general tips on Samsung LEDs, because they are the ones I follow. Samsung denotes each year's models with a letter, with the 2008 models being A. Last year's 2012 models were denoted with an E. The first two xx's are the size and the last four are the series number. Samsung series are differentiated with the 4000-5000 models being 60Hz sets, and the 6000 models being the step up models to incorporate 120 Hz motion smoothing interpolation features. Higher numbered series, 7000-8000, offer micro dimming to improve picture quality.
If you move up and add 3D, however, 240Hz models are recommended. Samsung also offers another smooth motion feature, LED smooth motion, which strobes the backlight. Unfortunately their marketing department "combines" the motion features, obfuscating the simple 120 Hz and 240Hz numbers, coming up with higher multiples, called CMR of 480, 720, 960, and 1200. Fortunately, most stores retain the 60, 120, and 240Hz designations.
Last year, however, Samsung offered edge lit LED models (ES) and rear lit (EH) models. The ES was also a slimmer model and the EH was a thicker model. The EH models had a semi matte screen while the ES models had a the glossy screen. This year's "F" models seem to be consolidated back into one line.
The key features to consider, in order, are:
1. glossy or matte screen
2. 120Hz for motion smoothing interpolation, 240Hz for better quality 3D
3. internet capability to get to the internet and stream video
More and more, it seems, however, as you step up to get a better quality picture, the 3D wi-fi, and smart features are also included, each running approximately $100. That's why I mentioned the F7100 as a solid model. Get out to some stores and look for yourself. FYI, Samsung has the biggest market share, followed by LG and Sony.