When I post updates to Twitter, my weapon of choice is Twitterific (Twitter: Twitterrific), free software by the guys at Iconfactory.

It is beautifully designed, and a joy to use. When I have something to post, I don't need to open a Firefox tab and browse to Twitter.com; I just enter my thoughts into the small Twitterrific box and hit enter. Voila! It also lets me know when my friends have updated.

Alas, it is only for Mac OS X, but I have a MacBook at home, and another at work.

Those of you on Windows or Linux: What clients do you recommend?