Echofon may look a little simple. And it may have a goofy name. And its interface isnt redefining any user interaction paradigms. But its still the only twitter client Ive found that brings together everything I want:
• Simple management of multiple twitter accounts.
• Great support for retweets, replies, and conversation threading.
• Fantastic list support.
• Robust support for searches and saved searches.
• Excellent notification options including dock badges, menu bar highlights, and growl support (even 3.0!)
• Easy navigation of twitter profiles, websites, etc.
• "quickview" like previews of attached pictures, etc.
• A minimalist interface that gives maximum space to tweets, yet doesnt require menu or keyboard commands to use, always shows a box to enter a tweet in, and easily fades into the background when I need to get real work done.
About the only thing it doesnt support is @name completion, which can be a drag. But Ive tried every other client out there, and all are missing one or many of the above features. So I always come back to Echofon.
Theres a free version, too, and its full-featured. It just displays ads. If thats your thing, check it out!