Hey, quick suggestion that may or may not have been suggested. I love firefox and that's why I love flock too. My main problem that keeps me from going straight to using flock 24/7 is because of this one feature. It's only in Firefox 3 (I currently use Firefox 3 Beta 5) and on their site this is what it says

Location bar & auto-complete: type in all or part of the title, tag or address of a page to see a list of matches from your history and bookmarks; a new display makes it easier to scan through the matching results and find that page you're looking for. Results are returned according to their frecency (a combination of frequency and recency of visits to that page) ensuring that you're seeing the most relevant matches. An adaptive learning algorithm further tunes the results to your patterns!

Now, I would love to see if this could be implemented into Flock. Kinda like this:

http://www.flickr.com/photos/plutor/2033698282/

Not my photo, but it is what I'm talking about. Typing in just a few letters will search the titles/urls for that letter(s)/word(s) and display it.