If you'd like to be able to vote without reloading the page, go to User Settings and enable quick voting.
Currently it only works in EKW and Jukka themes, though other themes could be added if you ask really, really nicely. It probably won't work in really old browsers, and definitely won't work if you have Javascript disabled. As is obligatory with anything vaguely "Web 2.0", this is beta. Send bugs, comments etc to ascorbic. If you like this sort of thing, you might also like themanwho's unofficial E2 Catbox Enhancer.