Bloc is another great map for snipers. Bloc is one big block-shaped map with two buildings on each side, both with a top and bottom floor, ideal for snipers. Walking out in front of the middle of the two buildings will usually always get you shot at or killed by a sniper. Alternatively, this map is also ideal for easy knife kills as snipers usually are unaware of the enemy behind them. This map is also great for matches like Search and Destroy.
This map is definitely one to sniper on. Although the two main buildings will be the biggest attraction to sniper in, I don't suggest you go there as people expect it. On the side of one of the big maps there is a sort of dip in a wall, where the light is quite red. There you can pick fellow snipers off and people running down the middle. You also have a good view of quite a few headquarters, on Headquarters. Lay down some claymores and you should get a large kill streak.