The speed difference between the 2 (2.66 vs 2.93) is not really much. 330MHz doesn't really spell the difference.
Let's take a look at what REALLY matters in terms of gaming:
Video Card: Both the 2.66 and 2.93 have the new Discrete NVIDIA with 512MB DDR3. It should be great for gaming.
RAM: Both have 4GB of DDR3. Also perfect for gaming.
Remember that games are GPU and RAM intensive and not CPU. The CPU's job will only be to calculate the game in terms of how interactive it is, and what the results of certain decisions or commands you throw at it.
The GPU is what makes those commands and inputs visible. It's the GPU that will actually render the game on your screen.
In short, behind the scenes stuff (running, walking, movement, selection of artillery, ANDs ORs IFs THENs ELSEs) are processed by the CPU. Even a 2.0 Intel Core 2 Duo should be able to accomplish all of those threads without a sweat. The GPU is what puts all of those calculations into a VISIBLE result by calculating shadows, triangles, depth, perception, fluidity, etc. That takes a whole other level of processing. The 512MB present in both models should more than suffice, plus the processing speed of the GPU itself.
If you have the extra cash to shell out for the 2.93, then you should go for it. If you do have that money BUT would rather spend US$500 on something else, go for the 2.66. You'll be fine either which way. =)