Now that's a good question...
Handguns: .22, .357mag, .380, .38 spl., .9mm (2), 40., .45acp, .45 black powder
Long guns: .22 (3), .303 British, .223, 7.62mm, 12 gauge, 16 gauge
If I counted right, I've got 17 guns.
I'd have to crack open the safe to be sure, but I think that's it. I'm saving for an Uzi to buy next. I've got a feeling they'll be illegal after the next election.