Gwibber - Gwibber is an open source microblogging client for GNOME developed with Python and GTK.
TweetDeck - TweetDeck is your personal browser for staying in touch with what’s happening now.
Socialite - History Ever since we acquired Socialite from Realmac Software in December 2010, we have been planning on releasing a faster, more stable version 2.
HootSuite - Enhance your social media management with Hootsuite, the leading social media dashboard. Manage multiple networks and profiles and measure your campaign results.
Earthquake - Terminal-based Twitter Client with Streaming API support. Only supports Ruby 1.9 and later.
Tweetbot - Sync your timeline across your iPhone, iPad, and Mac. Mute tweets by user, hashtag, tweet source, or keywords (including regex). 3rd Party support for image, video, read later, and timeline sync services.