I may be the last person on the earth to notice this, but the beta of A9 search absolutely rocks. It’s Ajaxy, interactive, and it lets me choose what “stuff” I want to see in the search results. The Wikipedia checkbox is definitely welcome, as is the Feedster addon tab, as those are two places I often search.
It’s not perfect though (but it’s “beta”), the layout could be a little smarter by default and I would really like the ability to rearrange window (column) location like you can with Google News. All in all though, I like it a lot. I don’t know if it’s enough to break my Google habit though.