1 So I can snipe well. One time on rats nest I stood on the pipes and had my friend go get me ammo.....good times good times
I use 2. I am accustomed to battle rifles and sniper rifles, so I need a sensitivity that goes fairly slowly, but can still react if I'm under machine gun fire. I think 2 is perfect because in slayer, what usually happens is that everyone is using the assault rifle, and when shooting advancing forward for a beat-down follow up. I find that if you walk backwards, they keep walking, and smart people jump out the way. 2 is perfect because you can keep the reticule on someones head while jumping, being push by a gravity hammer, ect. And if they jump out the way, you can quite easily follow them, emptying a few rounds into them while they try to escape your grasp on their KDR.
I play on either 3 or 4. I really don't see a reason to go any higher, since I've never had a problem, even while playing really high levels.
I used to be 6 in halo 2, but here on halo 3 I seem to have settled myself on 4, I played in it for so long that If i go up or down one, it seems to mess up my hand, I cordination.
Close range games, 5. Everything else is 2, it really isn't neccisary to have your sensitivity that high, having it low keeps your shots steady and percise, you cant beat me in br's.
I see that the default rules again. I know a couple people that play on 10, it takes some getting used to but it's okay for assassinations and such. I personally play on 4 so you can turn around quicker than 3 but still have the steadiness of a lower number.
I change it up a lot, anywhere from 1-6, depending on how I've been playing. If my sensitivity is 5 or 6 and I've been playing badly, I'll set it to 1 or 2 to improve my BR'ing. If it's at 1 or 2 and I feel I can't look around quickly enough in fast-paced games, I'll set it higher. I can play on 9 or 10, but there's really no point.