TweetDeck could be called Twitter on Steroids. You can monitor and manage all your profiles from one tab in your browser: follow, read, retweet & plan your tweets is a breath, just try it.
It also manages Facebook but I find it buggy for that.
Tweriod is a free twitter tool that helps you make the most of Twitter by letting you know the best time to tweet. It's possible to use it in combination with Buffer for an optimal effect.