Looks like the blotch problem is fairly common.
Mine that I sent back to Samsung today had the blue keys on top too, so it must be a newer version - obviously no guarantee of blotch free though. I wonder what the issue is? There's a post from a month ago on a US forum complaining about the same issue, so it must be an intermittent problem (or some happen to be manufactured with screens from a dodgy source).
The main reason I didn't want to return it at my expense and hassle to P*** is that even if they did accept it as a faulty, they'd probably just send me a new unopened one - chances are that'd have blotches too!
You're right though, once you know it's there you look for it, and can't live with it. I didn't notice at all for a couple of days, and almost said "sod it. I can live with it", but it's by far the worst screen blemish I've seen in years of using LCDs - usually light bleeds/clouding are near the corners and you sort of accept them, but this is right in the hotzone, and it's odd in that it's darker..
Also, who has their brightness above 2? That's more than enough for me!