Tweet Deck to view new Tweets, replies, mentions, and to post your own new Tweets. Tweet Deck lets you see Tweets separated into columns of mentions, hashtags, and lists that you've created in Twitter.
The second alternative to using the new Twitter interface is to use the Minimal Twitter Chrome extension or Firefox extension to remove the sidebar clutter from Twitter. In the following video I demonstrate how both Tweet Deck and Minimal Twitter work.
Here's how you can create lists in Twitter.