I am very ++ on this idea - not to prevent the need for scrolling all the way to the bottom, but for heavy voting days when I come across a node and I haven't too many votes left.
The scenario? It's a great post and has elicited a lot of answers, so I read through them all without voting so I can allocate my votes exactly where I 'need' to. Having got to the bottom I scroll back up again apportioning my votes. Then I have to scroll all the way down just to click the 'vote' button. If there were a vote button at the top of the page I could just scroll back up casting my votes and vote when I got to the top.