Personal Choice
The main tracker I use is AdTrackZWhy ?
Read an extensive report here
Special features
* If you are tracking PPC ads you can also check for fraudulent activity with AdWatcher
* If you want to optimize your site conversion use KaizenTrack
* If you want to offer a tracking service to others whereby they can login and see their own reports look at ezTrackZ
A Tip For Newbies
If you are new to ad tracking and want to quickly check how it can be profitable for your business then you can sign up for a free trial version with a tracking service such as AdMinder or HyperTracker.