If you snipe by hand, open two windows/tabs, and arrange them next to each other (or on different monitors, if that's how you roll.
Window #1 is the auction page.
Window #2 is the confirm bid screen, with the stupid high bid.
Refresh window #1 to update the clock.
As soon as you want to snipe, confirm the bid in window #2.
The closest snipe I've ever pulled off was 4 seconds (bidding on something for my mom.) But that's not my best snipe.
My best snipe was on my cell phone. With a minute to go, the cable went out... so, I fired up Opera Mini, logged in, and just placed the bid.
Got the bid in... with 7 seconds. And I wasn't even really sniping at that point.