The 8 series cards have 3 clock domains that can be altered: core, shader, and memory. The standard (stock) clocks for the 8800GT are 600MHz, 1500MHz, and 1800MHz respectively.
Usually the core and shader clockspeeds are linked, so if you increase the core clock then the shader clock rises with it at a rate of 2.5x the core clock. This is not always the case though, especially with factory overclocked cards like the one from Newegg that you listed.
To sum it up, the two cards that you listed are both 8800GT cards, but the one from Newegg is factory overclocked with a better cooler. No big deal though, you can use RivaTuner
to overclock any card yourself. It's easy and free.
By the way, yes, faster is better