Brooke Vibber 
too fancy mouse that has a button that switches scroll wheel between "normal" and "shitty" modes
Mans R@brooke Mine switches from stepped to smooth if you spin it quickly. Works surprisingly well.
@mansr one of my mice did that autoswitching and it drove me nuts :D but i fidget with the scroll wheel ;)
kepstin@brooke @mansr with the modern logitech ones, you can configure the autoswitching (adjust the threshold, or disable it completely) if you like. I'm pretty sure the button which switches between stepped and smooth modes can be remapped to do something else if you prefer, too.
If you're on Linux, Solaar is probably the best tool for tweaking Logitech devices.