Aether Vial counters.

[citanul]

The ability of Aether Vial checks the amount of counters. If you destroy it in responce to the trigger it will search for the last known information and so the ability will still resolve as normal. That I get.

But what about Vampire Hexmage? If I sacrifice that in response the trigger resolves and checks only to see 0 counters on the Vial so the player has the option to put a creature into play of 0cmc?

[Otter]

Correct. If the Vial is still in play when the ability resolves, the game simply uses how ever many counters are on it.