I am a huge gamer and I had bought this same set cause I though it would have been good. Unfortunately, this set is not a good set for gaming...well at least I did not have a good experience with it. The tv produces a lot of blurr and ghosting, especially in fast games and games with plenty of dark areas (gears of war 2, resident evil 5, killzone 2, etc.) It was so bad I had to call samsung and explain the problem and they had a repair guy replace the entire panel and it didn't help the situation. So in the end I returned it. Gaming mode didn't help neither.
Right now I am looking at the toshiba 40xv645u, I have great experience with their 42zv650u (though I returned it cause for my place I could go with something a little smaller and a lil cheaper.) But I wouldn't recommend the b550 for gaming, maybe someone else has had better luck with it than me. In event you can probably see what esle samsung has to offer or take another brand into consideration. Just my 2 cents..hope it helps.