For your first question or statement, you have heard calibration is extremely important.
There are really mixed views on that, I know of a LOT of people that took the Plasma or LCD out of the box, followed the directions for basic set-up (you know plug it in turn it on, scan channels, set the time, etc) not picture tuning except to make sure to tell it if it asks that this is in home and not in-store, so it sets the defaults to what a typical home enviornment is like.
This was it for them and they are very happy with the picture and never did another thing.
Before I get in to it too much, I always suggest that folks wait at least a couple of months before paying for professional calibration, no matter how tight they make the electronics, stuff is going to settle in for that time frame 2-3 months and pretty much blow your calibration if you have it done on install day.
That said, their the the next level of calibration, user calibration and of course there are pro's and con's to that and people with religious views on it as well.
User calibration is basically going out and getting something like DVE's HD Video Essentials Calibration Disc in Blu-Ray and using just the user set-up menu's, follow along with the desc and adjust it best as possible to match what they say you should be seeing and what you are saying.
While this is a step-by-step process it can also be hyper-advanced depending on what you consider hyper-advanced. If you have never calibrated a TV then chances are you will find your first attempt taking several hours at least. The good news is if you don't like the results you can just pick to option to reset all video setting back to factory.
Calibration is a balance of art form and technical, controls like color temp, tint, color, brighness, etc all inter-act with each other to a degree, it is really only by experience you get a good feel and then can cal a set in less time and get a better result.
If you hunt around on many sets you can find your way to the "Service Menu's", I would not suggest this and while there should be no control to damage your set, there can be, so if you are going paste where the "user menu's" take you, then you should hire someone.
The final option is to pay someone, the upside to this is that will have additional tools you don't have for really dialing in the picture as well as access to settings you may not even get through a service menu.
The downside is you might not like the result and while you can change it all back, you will have wasted your money, since as I said before it is a combination of an art form and technical not all calibration people will be equal.
Then there is one final factor in all of this, well many actually but the final one for basic calibration is what you like. Just as most people don't use tone controls or an equalizer to get technically perfect sound, they use them to get sound they way they like it, this is why I look at video cal standards (and there are standards) as a baseline and then adjust to my liking and to various lighting or program material.
So the first thing I would suggest is get your TV, go through the burn in period, I would not use a disc for the burn in, just a channel that you zoom or fill the screen with that does not have a scroll bar and runs 24 hours if that is how you d3ecide to burn it in.
With no cal disc at all I would see how you like the picture, the TV has 4 or more sets of pre-set picture settings with factory calibration levels set for everything. Like you might have a Movie, Soft, Hot, Game, Sports, lables like that. This is not calibration just user options that change a bunch of settings grouped under a lable.
Watch some TV, watch some Blu-Ray movies under ideal lighting conditions and then some under less than idea, watch some upscaled movies, some no-HD and some HD from your cable or sat, etc.
Use your built in factory settings for all of this and try out different modes, like Movie or Game or Sports, and get a feel for your set, then you will be in a much better position to know if you need/want calibration, what you want calibrated and under what conditions you want it calibrated to.
There is no hurry on Calibration.