Colorado = 1 deer per year. Licenses will specify whether it's a buck or doe tag, and you only get ONE, not one of both. I put in for deer this year but didn't draw ANY license.
Virginia = up to six deer per year. It all depends on where you hunt and what you hunt with. If a guy hunts archery, muzzleloader, rifle/shotgun, and then back to archery, and hunts in areas which require does be shot before a second buck is shot, a guy could bag all six deer, conceivably. I don't know anyone who has done it, though. As you can see, Virginia's laws are quite complex.
Iowa = one deer per year. Some licenses are buck only, some doe only, and some "any sex" (i.e. the first thing you see and shoot fills your tag).
I've hunted in all these states, but it's been awhile since I hunted in Iowa. Perhaps it's changed.