[chaosmachine]

From what I've seen, it only takes 1 upvote to hit the front page, and stories (if they aren't killed) tend to stick around for at least 24 hours. My hypothesis is that there isn't a best time.

[kwamenum86]

"only takes 1 upvote"

I would say it only takes one quick upvote. A submission with 2 or 3 quick votes after submission gets a big boost.