One of the best things about Macbooks is a fantastic Apple trackpads. Unfortunately, this cannot be said about third party mouse support. Maybe I haven't used Macs for long enough, but I really hate mouse scrolling (and tracking) acceleration. What I want is linear predictable scrolling and tracking, regardless of how fast I'm moving the mouse or scrolling the wheel.
Update - April 2020
I had to revisit the same topic on macOS Catalina (10.15) and unfortunately, neither Microsoft IntelliPoint nor Smooth Mouse were kept up to date with support for modern versions of macOS. Accelerated tracking doesn't seem to be an issue anymore, but accelerated scrolling is unfortunately still with us...
After a short investigation, I found a little utility called Smooze which does exactly what I needed (disable accelerated schooling). It has some other mouse customisation options, but I have no need for any of that. Smooze is not completely free, but at $5.87 I would say it's very reasonable...
Since I was using Microsoft mouse, the first thing I tried was Microsoft IntelliPoint mouse software for Mac.
The software recognised my mouse with no issues and clearing "Enable accelerated scrolling" checkbox restored linear scrolling that I was after.
The bad news was that pointer tracking was still suffering from the acceleration "feature". Maybe it was just me, but it actually felt like installing IntelliPoint made tracking acceleration even worse.
After a bit more research I downloaded Smooth Mouse application.
Setting mouse acceleration to "Off" actually made mouse movements quite jerky, but setting it to "Like in Windows" worked perfectly.
That was it - these two free applications made my external mouse work and behave how I expected it to behave.
If you use a non-Microsoft mouse, IntelliPoint will probably not work for you. What you could try is USB Overdrive software. It was next on my list, but since I achieved what I wanted with above free applications, I haven't tested it. The full version costs around £14, but you can try it for free to make sure it does what you need.
Mac OS X Yosemite (10.10)
Microsoft OEM Optical Mouse