We should recover close votes cast on questions which are deleted by the owner before actually being closed.
For example, a user posts a question, and I think to myself that it looks familiar. A search turns up one (or several) pretty clear duplicates, so I vote to close and provide the link to the older question(s). A short time later, the OP comes by and realizes that their question is, indeed, a duplicate and decides to delete it.
What I don't like about this is that I've essentially "wasted" a close vote. Now I'll admit, I've never actually used all my allotted close votes in a day yet, but it's a little disappointing to know that I've effectively squandered a vote pointlessly when it could have been used for something more productive instead (i.e. a question that really ought to be closed for whatever reason).
I suppose there's also some hypothetical room for abuse of this current mechanic (trying to force people to waste votes), but with moderators on the boards I think that's a non-issue.