I am a fan of Tweetdeck. I use their services for personal and business purposes. The UI is very slick and I can manage multiple accounts seamlessly. A couple gripes would be 1) scheduled updates don't work for my Facebook page 2) maybe this is a Twitter restriction, but I don't think the desktop version Tweetdeck lets you access search.twitter.com (hopefully I just missed it!) - which forces me to then go to the Twitter web interface. But other than that, TD is good stuff. I also like that it works well on my iPhone. When I'm on the Caltrain I can just be Tweeting away, which makes me productive even when I don't have Internet access!