Metro 2033 has its own built in benchmark also, you can disable physix as well as set it up to test any settings. Its also a full multi-core game so its very GPU dependent.
Showgun 2 did pretty well on high, 60% on one core, and 40-50% across the other 7. Maxed out on ultra, it pushed one core to 100% but strangely enough was a higher fps average.
Starcraft 2 has a tendency to run on as few cores as possible, runs better across 3 cores, but still tries to max out one before the others, especially when more cores are present. All truth, its one game that punishes you for having multiple cores.
http://www.bit-tech.net/hardware/cpus/2010/08/18/how-many-cpu-cores-does-starcraft-2-use/2
If your testing GPUs, its best not to use games that are cpu bound, SC2, Skyrim...
Civ V is an interesting one, but its buggy with crossfire, won't crossfire when zoomed all the way out on a map, but does when zoomed in. As such the built in benchmarks won't run in CF even though it does increase the cpu usage.
BF 3 is definately a good one to use for gpu testing.
AvP, Hawx 2, Dirt 3, R.E. 5 are also less bound to multi core cpu and more for gpu testing.