1920 X 1200 is only a little better than 1920 X 1080. To the casual gamer, it's not going to matter. If you're a professional, then it does matter. I run 2048 x 1152. It's just a little wider than 1920 X 1200 and I don't really notice that much of a difference.
The only reason why 1920 X1080 exists is so people who can't afford 1920 X 1200 can watch 1080P videos at a lower cost.
I actually own both those monitors. I like the Samsung one better, but I bought it for $180 off TigerDirect when they had a sale. The Samsung one has better colors. It looks smaller, but is much wider than the Gateway. The colors on the Gateway looks off to me, which was why I got the Samsung. I would go for the Samsung. Prices have gone up in the pas few days. It's usually $199 shipped.
The Gateway has HDMI and Component input. The Samsung only has DVI and VGA input. The stand on both of them suck. They both come with Touch Sensitive buttons, which can kinda suck too. It sucks more on the Gateway. The Samsung one is pretty responsive compared to the Gateway.
Dell had a sale on the Samsung monitor too for $183 shipped with a free Logitech wireless keyboard and mouse about 2 weeks ago. It's gone now.
Oh, one last thing...The Gateway has picture in picture which comes in handy sometimes, but is a pain to change back and forth because of the touch buttons.