I'll add my troubled MBP to the mix. It's had the screen flicker (top 1/4 of the screen) for as long as I can remember. It's a toy so I'm not sitting in front of it for long streches, but it was getting worse in February so I brought it into my local Apple Store. They decided to change out the logic board, turned it around in two days.
Got it back and there was no flickering for a few days, then in slowly returned. Back the Apple Store in March, again they replaced the logic board, having the computer ready for me the next day.
A few days of unflickered bliss, then it returned only this time the screen went completely black for 2 or 3 seconds a couple of times.
Called Applecare, they said send it in and give them one more try and repairing it, if that fails they'll start the replacement process.
Currently it's sitting in Memphis waiting for a part. Funny that the local store has the parts but the repair depot does not.
While it's a hassle, Apple has been very good to deal with, just thankful I bought Applecare to keep the warranty going until 2012.
Good luck everyone.