I've had firehose access at the highest level they give to your average developer for a few months now. We've been using it to grab every link on Twitter, but we still miss quite a bit due to rate-limiting (I would say 1-5%). I wonder if this firehose access is every single tweet. If so, it'd be worth paying for.
For those interested in preparing: <a href="http://apiwiki.twitter.com/Streaming-API-Documentation" rel="nofollow">http://apiwiki.twitter.com/Streaming-API-Documentation</a><p>Just so you know, the "Gardenhose" (a spam and relevance filtered stream) is already available: <a href="http://stream.twitter.com/1/statuses/sample.xml" rel="nofollow">http://stream.twitter.com/1/statuses/sample.xml</a>