Do not go by what a TV's picture looks like in the store, as all TV's have "store mode" that cranks up brightness/backlight/contrast/etc to insane levels and actually looks terrible at home.
I prefer local-dimming LED-LCD televisions, and my home theater has a 55" LG unit that is 10mo old, 1080p, and 120hz refresh rate. The artificial motion blur "enhancements", well, I do not like or use them. I have never noticed an issue with 120hz vs 240hz, as with the former the screen is refreshing 4x per frame (or more w 24fps TV and 3:2 pulldown). The ONLY advantage 240hz has is for 3D so that each eye gets 120hz instead of 60hz.
I really look forward to the OLED units but will not buy one for 2-3yrs after they are released, as I would want the tech to mature and, for $6-10k I would rather get a high end DLP 1440p projector and have a 160" screen... (biggest I can fit with basement ceiling height)
LG has been who I have bought my last 5 TV's from, all LCD/LED and over 7yrs with all still in use, not one dead pixel, bulb/lamp, or any other problem. I highly recommend them.
Also, look into, at the very least, a decent receiver and a 2.1/3.1 speaker setup. Denon, Onkyo, and Pioneer are the best receivers for the price, and I still use a Pioneer VSX-D509S (despite having 7.1ch, a 7.2ch, and 9/11.3ch receivers) as a backup as it puts out a measured 160W+ per channel, 50W more than it is rated at, and drives my Cerwin Vega VE-12's like a champ. My other receivers require me to setup my McIntosh amps to drive a full system. Btw, the CW's are used for stereo while I have Definitive Mythos II, JBL, and Martin Logan towers I typically use as fronts with surround sound as they are much easier to voice match.
A 5.1-7.1ch receiver pushing 110-150W/ch can be had for $300, with a set of decent front towers costing $250-500+ depending on what you want. I love the Cerwin Vegas bc they do not need a sub and sound loud but clean. You can get the same model for around $300/pair. Or, get a pair of Polk Monitor70 Series II (or 60) on sale for the same price, a CS2i center, and a 12" subwoofer and you will get excellent sound. You can always get nicer towers down the road and use those as surround side/rear, or get bookshelf speakers for surround. I use 6 towers (Fr L/R, Surr L/R, RrSurr L/R), 2 JBL Studio Monitor "bookshelf" (Front High), 2 KEF Omnidirectionals (Front Wide), a 6-driver center, and a mix of 10" and 12" subs. I simply cannot go back to tiny surround speakers, towers are a thousand times better, so long as you have a strong signal.
I would avoid plasma, I personally think the picture looks a little "washed out" even on top-of-the-line sets compared to good LCD although I am constantly around LCD displays (car, home theater, 2x24" work monitors, 2x24" I-IPS and 1x30" IPS home monitors, etc) so maybe I am just very used to the look...
Avoid 3D, not worth the money and is a gimmick. Spend the extra on a receiver and some good speakers. I promise you will be MUCH MUCH more satisfied.