Here are a few of my favorite AdWords tools:

Winner Alert

Automate your ad split testing. Stop trolling through dozens of campaigns and ad groups wondering whether a split test is done. Hook up Winner Alert in 5 minutes and receive automatic notifications of significant results. It’s like a whistling tea kettle for AdWords. I helped make this one.

The AdTool

Generate hundreds or thousands of keywords, lower your bid prices by finding less competitive keywords, peel and stick them into their own ad groups. A powerful tool for anyone who’s constantly going into new markets. Includes Keyword Discovery results! I helped make this one too.

KeyCompete

Find out what keywords your competitors are bidding on. Chances are they’ve thought of hundreds of good ones, spent a lot of time and money creating a comprehensive keyword strategy, and you can see it all just by typing their URL. Doesn’t seem fair.

AdWord Accelerator

Find keywords you can afford - that you never would have thought of on your own. You’ll be surprised what’s available for a song! You’ll be able to play in competitive markets with this tool.

WordTracker and KeywordDiscovery

Very similar tools that allow you to discover search volume and variations for online markets.