I actually don't think you can pick and choose when you go to the Apple Store. You can buy one, open it up and, if you're unhappy, maybe exchange for another one. But there's no way to tell what LCD a computer has without opening it up and checking. Similarly, Apple uses whole bezel replacements most of the time and they do not normally indicate what LCD is being used. I was being helped at the Apple Store and though they were doing everything possible to make me happy, they told me that they had to put the LCD on the computer to check the model and that there was no way to specify a specific LCD for replacement. They simply don't know.
Having said that, this is my brief summary of the LCDs discussed, and ones which I've personally seen over the last year:
15.4" " 09c60 AUO - the most common it seems. Main issues: very grainy, slight uneven backlighting, poor viewing angles. Did not like this display at all because of the above. I had several and they all gave me a headache and eye fatigue.
15.4" 09C57 - ChiMei (not 100%certain) - 2nd most common. Main issues: bright strip at the bottom of the screen, slight unevenness from left to right, grainy but better than 09c60, relatively poor viewing angles . I had two MBPs with this display and while they were a little better than the 09C60, they were still pretty poor. Didn't find it as objectionable as the 09c60 though, maybe because the grain was less.
15.4" 09C56 Samsung (haven't personally seen this one) - apparently less grain, even illumination and acceptable viewing angles. I'd like to see one to be true believer.
17" 09c 62 (LG-Philips) - Almost no grain, acceptable viewing angles, uneven illumination, bright strip at bottom (though I've had two now, one with a bright strip, the other not - in the store it's about 50/50). This displays is fine and, of all the MBPs I've had I like it the most because it's sharp, doesn't distort as easily, nice brightness and no grain. VERY easy on my eyes, comfortable to sit in front of for longer stretches. The only thing that would make it a genuinely *good* screen would be if the illumination would be more even. Still, it's not bad - just not great either.
17" 09C61 - don't know much about this one. Some say it's good, some say not.
Hope this helps.