If you go to AVS for any plasma, do the 100 hour burn-in first or their settings won't be quite as accurate.
Now, I'm not going to say that if you don't follow their steps to the letter your TV will be unwatchable, or that those settings won't work just as well, but if you're looking to get the best results you possibly can without paying a professional, do the burn-in. Essentially, the individual pixels on a plasma TV will "mature" through use. Typically after 100 hours they have matured as much as they are going to (or close enough that it doesn't matter). If you watch movies with black bars at the top and bottom (tons still do because of the different aspect ratio on movie screens, even though you don't realize it), if you play video games on it with a UI in the same spot all the time, or you watch a news channel with a colored news bar a the bottom...all of those things can cause the pixels to mature differently than the rest of the screen. Thus, they recommend cycling it through solid colored slides (usually via a USB stick, download the slides from AVS) so that every pixel is matured the exact same way, which ensures that you are working with the same exact base starting position they did when determining the settings they posted on the forums.
Will you ever notice the difference? Doubtful, but videophiles say they can. I love the way mine looks, but I would imagine so do millions of other people that never even knew those forums existed. Whatever you decide to do, one thing to note is that almost everyone that sets theirs by feel sets it way too bright. Bright looks good, it stands out, it lets you see everything without effort. But it also isn't the way it was intended, just like the loudness button isn't how music is intended to be heard, even though it sounds so cool at times. If you use the burn-in time and their settings, a lower brightness setting should still allow you to see everything you were intended to see perfectly (unless your vision stat sucks).
So if you're going to use their settings and don't have your own calibration tools (or the desire to pay someone else to do it), it isn't really that big of a deal to let it run for 4 days before you start using it, assuming you still have something else you can watch in the meantime.