XSitePro Analytics & Ad Tracking

Adtrackz - My favorite ad tracking software by far. I've tried all of the others, and I like this one best.

LinkTrackr - A hosted link tracking option. Great for affiliate tracking.

Google Analytics - You can't beat Google's own free Analytics software, unless of course you want to spring for something better, which would be Urchin (see below).

Urchin - Google bought Urchin and turned it into Google Analytics, but the original is still around, some of the higher end hosts will sell you Urchin analytics, get it if you can afford it.

AdSpy Tracker - The best way to track where your Adsense clicks are coming from, and protect your sites from click fraud.

Google Webmaster Tips - 5 essential tips when using Google Webmaster Tools.