Let the mobo autodetect the memory settings. It should detect at 200mhz fsb, and cas settings of 2,2,2,6 with 1T command rate. That memory is very good so you should be able to use the fastest memory setting if it doesn't autodetect.
Without going into the ugly details, lower is faster for most memory settings except FSB speed. 1T is faster than 2T, cas 2 is faster than cas 3, etc.
The second stick of memory will just let you run the memory in dual channel mode, meaning it accesses both sticks of memory at the same time which theoretically doubles your transfer rates.
In another thread, skuzzy mentioned that at a certain point, you don't get better framerates with newer generations of vid cards because if you have a better vid card, AH automatically switches to a different rendering path that improves vid quality to take advantage of the better vid card. That means that a newer vid card may only get you improved quality, not better framerates. Obviously he couldn't list any details of what exactly changes, however he said that within limits, AH will abuse the heck out of the vid card which is why 2 people, one with a 9600 and one with an x800, can set their ah graphics sliders to the same spot and get very similiar framerates - the guy with the x800 is apparently going to get better image quality at any given framerate.
I could be misquoting skuzzy, but that's what I understood from his post.