Let's see...
I have a huge monitor, so 800x600 is very pixellated for me, but I use it anyways. I need a new motherboard to get my new video card in this pathetic rig, so I lag at a higher res because of it.
With my Microsoft BETA Optical mouse, I ran a sensitivity of 4 with my mouse settings at medium. I use a scope rate of .5
With my RAZER Copperhead, I run 1.7 with freaking fast mouse settings, although I take advantage of the on-the-fly adjustments depending on the gun I'm using. I use a scope rate of .5
With my friend's Logitech G5, I use a sensitivity of 5.0, but I rely on his windows settings and the on-the-fly adjustments.. He keeps his windows speed really freaking low for some reason, so I must compensate.. I use a scope rate of 2 for some reason..