This is a good time to plug the wikipedia easy search plugin that I like. You just make the text below into a bookmark (these are known as bookmarklets). Then I put the bookmarklet in my browser favorites bar, which I can access with key commands (depends on browser). So, I just press command-3, and then a little box pops up, into which I can type my Wikipedia query, and then press enter to search. My hands never leave the keyboard.
Code:
javascript:void(q=prompt('Wikipedia:',getSelection()));%20if(q)void(location.href='http://en.wikipedia.org/w/wiki.phtml?search='+escape(q))
Bookmarks