1. Tweet Deck - a complete control panel that will let you put your tweeting on steriods.
2. Tweet Later - Twitter automation including auto thank you  messages to followers.
3. Twollow - will search Twitter conversations for specified keywords and auto follow participants.
4. Your Twitter Karma¬†- make sure your reciprocating with follows and purge those who don’t.
5. Twitter Feed - will pull RSS and data feeds and create Tweets that will post automatically.
6. Twitter Tools - plugin that interfaces your Twitter account with your blog.
7. My Tweet Space - free customized Twitter backgrounds.
8. Twitter Buttons - free Twitter logos and graphics for your websites
9. Twit Pic - share pictures on Twitter
   
10. Twitter Counter¬†- your “followers” stats along with predictions of how¬†

Original post:  http://jtmartin.net/top-ten-twitter-tools 

Changed in the order i think is best!