[jrockway]

I think I find the ceiling method most intuitive. I have noticed that video games with cooldowns tend to agree with me; some ability has a 4 second cooldown, you press it, and the UI says "4", even though 3.999 seconds remain until the ability is back. (This means that you never see "0"; the counter reads "1" for the last second before the cooldown is available again.)

[shirakawasuna]

The ceiling method matches with the expectation of how much time is left when the major digit changes, which is the same as how we do countdowns verbally in English.

We say, "5, 4, 3, 2, 1, 0", not "4, 3, 2, 1, 0, done".