For memory upgrade: faster memory ok?

I'd like to upgrade the memory in my iMac 2.8. I am shopping at a local computer store, but they seem to be out of the 667 Mhz memory, but have the 800 Mhz on hand at the same price.

The description of the memory from Crucial is as follows:

4GB DDR2-800 (PC-6400) Memory Kit (Two 2GB Memory Modules)

Would there be any reason to avoid this purchase and stick with the 667 Mhz?