Don't worry, you didn't buy the wrong TV. I'm sure the salesman (oh, sorry, . . ."expert") at the store told you that the LCD was "Better" than the plasma. And here I see a lot of plasma purists with good opinions and great intentions trying to tell you that the plasma is "Better" than your LCD. Don't get me wrong, I love my plasma, and it's the only choice for my particular room. But in your situation, an LCD could be the right choice.
I'm not going to give you the whole lecture from soup to nuts. If you want you can read it on my site, www.AVEndUser.com
. But to put your mind at ease, what you really need is a professional calibration. Your LCD came from the factory in FLAMETHROWER mode, and in your living room is virtually unwatchable. For starters bring down the color saturation , contrast and "sharpness" to a reasonable level so you don't go blind before you can do the job right.
If you don't want to pay a pro, you can do a semi-reasonable job yourself. Go buy a copy of Digital Video Essentials for Blu-Ray (maybe $26 online), and follow the instructions.
The one thing you won't be able to do is set the white color temperature. You need a lot of expensive equipment to do it right, so just take a stab at by sight. But you will get the red green and blue levels closer to correct, and the contrast where it aught to be.
Lose those cartoon colors and processing artifacts, and you'll learn to love your LCD.