Great article containing tips on how to configure Twitter (using third-party tools) to reduce the number of tweets you are consuming:

http://blogs.sitepoint.com/2011/01/14/5-ways-to-make-twitter-less-noisy/

However, before leveraging another tool, definitely take a look at unfollowing content providers that are offering little value. And, most importantly, use lists to group your content into multiple streams. This is a great way to manage multiple topics.

Finally, bring in the horsepower of another product as a last result. A tool like Radian6 can let you monitor literally thousands of tweets and users at once and alert you to “only the good stuff”. But be warned, tools like Radian6 and the many others out there require a fair amount of time to manage so that you can configure them accurately enough to deliver what you are looking for and to avoid the stuff you’d normally pass up. If a monitoring tool or service is consuming too much time, then you’re not getting the right value out of it.