Hoothoot in Pokemon Gold. That was the first pokemon I ever caught. Not Pidgey, not Rattata, but Hoothoot. It was a staple in my first team, and I raised it to Lv. 50 something before my file got deleted by something. (This was way before the batteries would go out. My Gold still saves fine.) Meganium was Lv. 100, and Ho-oh was at Lv. 91. Don't remember any other levels, though.