Yes, I have an optical mouse (I’d never go back to a ball mouse now) with a scroll wheel and side buttons for left/right scrolling.
I only use the wheel and scroll buttons for fine adjustments though; I have to work on very long documents and the scroll bar on the screen is still the best way of getting about.
All the time. I love my mouse wheel. I haven’t touched a scrollbar in years.
I have a Logitech optical mouse w/ a scroll wheel too, and my life would be seriously deprived if I didn’t have it. I’m mostly indifferent towards technology type things, but holy god do I love my optical scroll-wheel mouse.
The scroll wheel kicks ass. I have an optical Logitech mouse, and it rocks. As with Mauvaise, I sometimes find myself trying to use a non-existant scroll wheel. Non-wheel mice are now a pain to use. And, as Sultan Kinkari states, it is useful in FPS games. I always bind the wheel to change weapons.
The scroll wheel: computer gadget of the gods.
Lunatic13, do you have an cordless optical mouse? I do. 
Oh yeah, got one o’ them too. Have a “normal” mouse at work, and hate it!
I couldn’t live without a scroll wheel now. (Well, I could, but you know what I mean.)
I use a drawing tablet now, but I used to have a mousewheel. However, it got gunked up or something.
Someone told me that the reason mousehweels made of rubber sometimes stop turning is because the moisture from your hand causes the rubber to expand slightly, thus jamming it.
So there ya go.