If you're going to be picking up the Samsung Galaxy S II you'll notice that the screen is a little crispier than what you may have seen before. The science behind the reason all comes down to Pixels. Samsung have deployed a pixel scheme they have titled Real-Stripe and this introduces regular old pixels for all colours, Red,Green and Blue which gets rid of the granulation issue caused by PenTile in older Amoled screens. Although this is good it means that it will only be seen on larger screens and would explain why Samsung went with 4.3 and 4.5 inch screens.
Although this is good we need to get battery issues sorted. it's all well having a phone that has a clean and crisp display but people will want to look at it. The more powerful a phone gets the more power they will need and i doubt very much you want to charging your phone every 5 minutes.