I love "Midnight Run," with DeNiro and Charles Grodin. It's very much a road/buddy film, much like the old Crosby-Hope films, but it's also got a fair amount of mob life depicted. Dennis Farina was FANTASTIC as the Chicago/Vegas mob boss.

Also, "29th Street" is one of my favorites that mixes the genre. At times it's almost a holiday film about a blue collar Italian family from Brooklyn (Capra meets Scorsese?), but it's also loaded with mob life. Danny Aiello was stellar (in my opinion, his best role ever), and look out for a youngish Tony Sirico as a low level mob goon sent to collect money from Aiello.