Weapon switch.

[dfour]

scroll wheel but im trying to wheen myself off them as the numbers are so much quicker

[Teh_Diplomat]

Knife to side mouse button
Pistol to the middle (click of course)

That keeps me alive in 90% of CQC situations.

[Skaggy]

I'm getting accused of macro's due to my quick weapon switching now :|:.

[DarQraven]

Custom binds ftw. I have this nice flashy Zboard Fang that has about a gazillion buttons to bind weapons and actions to, and most you can reach without ever letting go of the arrow/WASD keys.

So yeah, custom keybinds are definitely the fastest for me.