what sensitivity you prefer for mouse?  

I used to play cs 1.6/css and I used to use 3.3 for my sensitivity. It's all about preference though, but keep in mind you should be able to do a 180 degree spin with your mouse and thats your perfect sensitivity.

I used to play this game way back before CS Source came out. We have to rent a computer in a computer shop that houses 20+ PCs with a dedicated server as a host to prevent lagging. I personally use 10 as sensitivity but I do change other settings too. I prefer to use 10000 as forward, side and backward speed. I even change the yawspeed to 10000. This is my prefered setting. I dunno if changing the other settings will help but make sure the forward, side and back are the same so you can move smoothly in a diagonal manner.

When I played CS, I was used to 10,5.

Sensitivity doesnot matter much to me. . All you need to have is a good mouse

this actually depends on the type of mouse you're using and the mouse speed set in the mouse settings..im usually on the very lower side ..between 1 and 2.5

I paly counter strike from five years ago . I use to play with 4-5 sensetive for the mouse . I think that is good sensitie to play better. The best player play with small sensetive just like me :D . Have you ever hear for the player Sk|Spawn ?