TweetOBox is an attractive new Twitter client, with a stylish interface and plenty of features.
Once set up you're able to view tweets from everyone you're following, those sent to you directly, retweets and more. It's easy to search Twitter for more content, and you can save common queries for reuse later.
Just in case you still finding yourself losing track, TweetOBox will mark tweets as "read" and "unread" so you won't waste time scanning messages you've seen already.
And you can extend the program with plugins, to carry out tasks like preview web links or photos (although there are very few available right now).
Please note, TweetOBox is a beta. We experienced a few glitches, and you probably will too, but if you're in the market for a new Twitter client then this could still be an interesting alternative.