Around 2-5. The only ones that immediately spring to mind are Arkham Asylum (so, SO worth it to see Riddler get busted) and Avatar: The Last Airbender (the first one), which, in retrospect, wasn't actually terrible for a licensed game...
I don't play THAT many games, and when I was a kid all I ever played was Sonic and Pokemon. I have never, ever got a single Chaos Emerald in my entire life, and catching every single Pokemon? Ha! Dream on.
Although having said that, I intend to get all 156 this time around. Gotta catch 'em all!