I've been using the beta version of Microsoft's new MSN search.
Frankly, I'm impressed. And not just because my own sites do well in the rankings.
I've only been using it fulltime for a few days, but so far it is outdoing google. There are some searches where Google returns better results, and others where MSN returns better results. Considering that MSN Search is still in beta, this is pretty impressive.
If MSN Search returns better results, Google will have to tweak its algorithm. Quite a few of us think Google has gotten lazy about maintaining vigilance of its results' relevance.