I definitely plan on switching to gnip. As i said, tweetweather is just something I put together after work the past week, grabbing from the search api was the quick and easy solution to getting tweets into the system.
Can you explain how you'd use Gnip in this instance? From reading the API docs, it doesn't sound like you can do anything with Gnip + Twitter other than get tweets from / to a particular Twitter user. So you can't get keyword-filtered results from the public timeline, I don't think. Am I missing it?
Gnip rocks.