If we're really dreaming here it would be a Marco Polo
Dall Sheep. But, I work for a living, so, 15+grand for a hunt isn't going to happen. Maybe some day I'll draw a sheep tag here in Washington, but the odds are probably not. Luckily I'm realistic, and I'm happy just being able to hunt deer, elk, and bear every year.
Tahr, Chamoise and Red Deer in New Zealand are second place.
I am doing the Ibex hunt this year, my (next) dream hunt would be Desert Bighorn here in AZ.