I'm a pretty avid Twitter user and love my new Macbook Air (first Apple product I've used other than iPhone) but I've run into a bit of a snag. I like having a sidebar on my desktop which shows my Twitter feed. I use Echofon on my phone so I gave it a whirl first. While I like it, I don't like how when I begin a tweet and am mentioning another user, the program does not auto-finish for me like it does in the iOS app. For instance, if I am trying to mention Chris12345 I have to type @Chris12345 but on my phone I can merely type @Ch and Chris12345 will be an option that I can just click. This doesn't sound like a big deal, but it would improve my user experience a lot. Is there a Twitter client for Mountain Lion that includes this functionality? Perhaps I should also ask what the best Twitter clients are? The only other one I tried was TweetDeck, but it was a bit too bulky for my tastes.