there was no "Vote" button at the top of the page

Maybe the button is at the bottom on the off chance that people will read all the replies, and that maybe a reply posted at a later date is perhaps more deserving of your vote? Seems a pity to vote only on first posts.

In a similar vein, the voting radio buttons should be at the end of a reply, because it's only after you have read the node that you are in a position to make up your mind? In which case having to scroll back up (Whether physically or ocularly) is a slight useability problem.

I've always thought this should be user-configurable but having looked at the codebase I find the task of adding a new option to userprefs a little daunting. One of these days...