Friends, this is what you do.
First, get yourself a nice Logitech MX Revolution (I recommend Amazon). The MX Revolution is great because of it’s satisfying weight and ultra-nice scrollwheel that allows shifting between disciplined clicky-scroll mode, and ultra-fast gyroscope holy-crap mode.
Then, buy1 a copy of Steermouse
Configure Steermouse2 so:

You’ll also want to drop down to the command-line and re-enable the manual click-to-freescroll action in the MX:
defaults write jp.plentycom.SteerMouse LOGITECH_MX_REVOLUTION_WHEEL -int -3
1 The built-in Logitech drivers for the Mac are crap: marketing won and they don’t allow you to remap the useless i-search button on top; nor can you make a change to the default application settings that is ‘inherited’
2 You better not be crying about the $20 you just spent. We’re Mac users, we are willing to pay for nice things.