OCing my video card - is it easy?

The OC version is better. It's a better GPU that passed more tests. It will OC better. The basic one will run fine at stock speeds but can have issues when OC due to it's lesser binned components.

Yes, it's easy to OC a vid card. Using Rivatuner you easily can overclock the 3 clocks till you have reached your goals. And it's easy to overheat the 8800GT with an OC, unless you get a aftermarket GPU cooler. You can set the fan on the stock heatsink to run at 100%, making more noise from the small fan than you can imagine, and still have uncomfortable temps.

No, you shouldn't have an issue with 100mhz since the OC card uses the same cooler.

@Conundrum: in my experience it's usually not the core that's better, it's the memory. They tend to use better RAM on the OC cards to ensure stability at the speeds they want to sell at. At least that's the way it was with the 6 and 7 series NV cards.

Everyone remembers the terrible problems the 7900GT had with overclocking memory, right?

And 100Mhz won't be a problem, as others have said, but ensure the fan runs 90-100%. You should get the clocks for the shaders and the memory on the OC'd version, too, and try to match those.

Get the Gigabyte 8800GT that comes with the Zalman fan and is clocked at 700. Then you don't have to do *anything* except stick it in the case and load the drivers.