OK, so what guns have you owned and sold/gave away that you wish you had back?
For me, a Series 70 Colt .45 Government Model that I let go in a breakup. I replaced it with a Series 80, which was almost as good. But not quite.
A AR-15A2 that I sold when I moved back east. No real choice on it.
A 1980s PT-92. I sold that cheap to a friend who had stalker issues. She never had to shoot the guy, but she still has the gun.