Google! I also downloaded their tool bar so it's super easy. Also cool is that it comes w/ a little voter on it so you can vote for or against websites. . . of course I vote almost daily FOR tPF! LOL!
Google!! I think the others don't always find what I want, and to be honest...I don't know how to use them. The last time I used Yahoo and MSN, they had ads that jumbled up the page and I couldn't make sense of anything
Blingo. It's run by google, but you can win prizes for usingn them. I won a gift certificate to itunes last month through it.