If you're running OS X, you should hop on over to Ambrosia Software and check out iSeek. You know how Safari has that nice Google search field up in the corner. Well, iSeek gives you a search field up on your menu bar. And you can define any of a number of different search services in it. Type something in, hit enter and it brings up the query in your default web browser. There's also a nice key-command to jump to it no matter what you are doing. I've been playing with it for a few and I have to say I really like it.