i hate adjusted sensitivity, it should be adjusted scroll speed with the same sensitivity. The whole thing is stupidly designed, and the sensitivity jumps by massive hops.. (going from 1600 dpi to 800 in one click, to 400 dpi)...
I prefer to use quality mice anyways, and those are often called gaming mice, it is just a name though. Higher resolutions means three things. Higher initial mouse move speed, registering slighter movements, and less false positives (aka, moving on its own while not on a proper surface). The speed can be adjusted in windows properties, registering slighter movements doesn't really matter beyond a certain point (for me 800dpi), but less false positives is nice if you don't like the feel of a special mouse pad on your hand and have a table that is dark and smooth.