My dad use the logitech wireless optical and it's awful, not enough that it chews up battery like it's free, but the damn thing lag when you play games. you move the mouse and a second later it follow, thank god I played with his before going out and getting one.
Also it's too bad they don't make wireless optical mouse that would use a small 12V battery like the one in car remotes. It would last a while since it only need 3V, would a lot lighter because of the small battery and able to make the mouse small. I find the ones out now way too big and compared to my optical with cord, they are too heavy.
My fav is still the dual optical with cord. No clue about the keyboards, but make sure you will not have problems using more than one key at the time while playing, I exchanged a few logitech keyboards because of that and ended up with a MS Internet one. This one doesn't mind 4 keys at once while playing.

My next keyboard going to be the MS with even more extra buttons on it, got so used to hitting buttons to do/start something instead of using the mouse. Not sure about getting it cordless, but might try it and see.
<font color=red>Computer upgraded, now need a place to live, and a good divorce lawyer.</font color=red>