After trying out a variety of tools, my finger seems to gravitate to HootSuite on my Droid. Its interface is just simple and clean. I can flip between my home feed, lists, etc., and easily use it to post, retweet, and so on. It works well as a web app on the desktop, too!
That said, I've not explored the Pro version or spent any money. For what I do, the free version seems to be sufficient.