Most realistic:

Pussy (reminds me a lot of Angie Ruggiero)
Butchie
Phil Leotardo
John Sacrimoni
Richie Aprile
Jackie Aprile, Sr.
Carmine Lupertazzi
Gigi Cestone
Patsy Parisi
Hesh
Johnny Boy Soprano
Junior Soprano
Mikey Palmice
Furio
Larry Barese
Albert Barese
Ray Curto
Bobby Bacala, Sr.
Uncle Pat
Brendan Filone (as an example of the fuckups coming up now)
Murf Lupo (as an old timer)
Carlo Gervasi

Most unrealistic:
Tony Soprano
Silvio Dante
Christopher Moltisani
Benny Fazio
Ralphie Cifaretto
Tony Blundetto
Bobby Bacala, Jr. (too nice)
Vito Spatafore
Matt Bevilaqua
Sean Gismonte
Gerry Torciano
Little Carmine Lupertazzi
Little Paulie Germani