Twitter clients that can filter tweets by regex?

What is this for? You can use the search API directly (it works with URLs):

http://apiwiki.twitter.com/Twitter-API-Documentation

If you truly want regex support, just grab a lot of tweets with the API, and filter client-side.

I am looking for an existing Twitter client that can filter by regex while still having all of the bells and whistles. Building my own would be a last resort.

Checkout Yahoo BOSS, you can whip up your own client pretty easily in Python or Ruby.

Twitter clients on the desktop suck.

yorufukurou does regex and is generally tolerable (OS X) http://sites.google.com/site/yorufukurou/home-en

Apart from that, it's easy to roll your own stuff - for example using the tweepy python library.

BYO with Yahoo BOSS. Here's an example app: http://zooie.wordpress.com/2009/01/15/twitter-boss-real-time...