TwitBird Pro is a full-featured iPhone Twitter app that supports landscape view for tweets and the inline web browser. As they claim in the App Store description, landscape view is available on pretty much every screen of this iPhone app. If you are a fan of typing or web browsing with a wide screen on the iPhone, this is the twitter app for you!
Nomee collects many social networks, allowing you to focus on following people instead of websites. It tracks a huge number of social networks. Nomee does not cater to any one social network extensively, including Twitter. Still, it seemed appropriate to write up its actual tweeting abilities for those curious about using this social dashboard.
Nambu is a feature-rich Twitter app for Mac OS X that supports many social networks. It offers plenty of configuration options but has simple defaults for beginners. It also has excellent integration with its sister services, tr.im and pic.im
DestroyTwitter is a full-featured yet lightweight Adobe AIR twitter app. While many other AIR apps are guilty of being on the pudgy and/or sluggish side, DestroyTwitter is refreshingly responsive. Upon load it starts at about 40MB and after using it for a bit, searching, and loading a couple other columns it only climbed to 61MB. Very good for an AIR app!
Even though the memory footprint is light, it doesn't skimp on features. The app is maintained by Jonnie Hallman, an Experience Designer at Adobe, so that may have something to do with it.
TweetDeck is a feature-stuffed multi-column Twitter app for the iPhone. It is already a major desktop twitter client, running on Adobe AIR, with all the features anyone could ask for (including multiple accounts as of 0.26), so it seemed like they would spend all their time making a great user interface. They packed it all in there, but at the expense of usability. From their website:
Bitter is a lightweight Twitter client built on .NET, so it's Windows only. From the Bitterware site:
It consumes a low amount of memory, is theme-able, is secure (uses HTTPS for authentication and encrypts authentication details), uses a familiar tabbed-interface and so much more!
TweetDeck is an Adobe AIR Twitter app for power users. Using a column layout, TweetDeck allows a user to set up many feeds at once. Some are specialized to Twitter, such as your friends, @ mentions, direct messages and so forth. But the real power lies in their numerous advanced search features, which filter the public timeline any way you desire: