I once inteded to watch a mafia spoof starring Kevin Pollak, but turned it off after 20 minutes, because it was sooo bad.

Oscar is my favorite, and Analyze This is great.

But I think there are more crime/comedy movies than we'd think. Not only spoof movies or mafia related, but regular crime comedies (Snatch indeed) are great. You could count the humor parts of Pulp Fiction to this genre as well I think. I also LOVE "The Mexican".

And of course, The Soprano's can be funny sometimes.

Buddy Cop movies are crime-comedy combinations a lot (like Bad Boys, or Blue Streak)