H&R 20ga. Still have it, it does duty as home defense now, just so she won't feel neglected.
That lasted me a year, then Dad bought me an H&R16ga (that started my 16ga addiction) and a 12ga 870 Wingmaster that was my first "real" (as in more than one shot) shotgun - that one is for sentimental reasons usually my "opening day" gun.