Welcome to the forums, fredmania.
You might want to have a look at the Discworld games (
1,
2 and
Noir). They're fun and very good, though the first two are insanely hard.
Secret Files: Tunguska has conspiracy elements and nice graphics (though not cartoony), but there are some caveats (see the review).
I'm sure there are many more, but nothing pops to mind at the moment.