Here there is my top 10 twitter applications. I hope they are useful to optimize the time you expend on Twitter.

1. Twitterfeed: Update via RSS.
2. Twitdroid : Android application.
3. Twittercounter: Stats for your profile and featured users.
4. Friendorfollow: Check who is not following you back.
5. TweetDeck: Twitter Desktop application. Best ever folks!
6. Twitxr: Send pics to your Twitter profile via mobile or email.
7. Adjix: Schedule and repeat your twits. Do not harrash!
8. HelloTXT: Update your status on multiple socials like khaces .
9. Brightkite: Nice web and mobile aplication using GPS. Nice to update your location.
10. Socialoomph: Auto DM your new followers, Autofollow your followers.

If you want more read my original spanish article. Hope you enjoy it!