Samsung Galaxy S II hard case. It is a very slim case with a mesh style that gives it a nice trendy and textured look. It actually makes the Galaxy S II grippier and easier to handle. The case is so slim and light it almost feels like holding the phone sans any case. The mesh/holes not only look good, but will also help ventilate the phone. The Galaxy S II (aka Galaxy S2) does get warm at times - after all there is a 1.2 GHz dual core processor ticking inside.
Case-Mate Touch Case or one of those cheap knock-off gel cases you find in the local market stall.