The only movie I remember well from the Platinum Collection is "Port of NY," a very decent B-movie with Yul Brynner (with hair, no less!) as a pretty convincing and intelligent gangster. All of those movies should be worth watching--US B films on gangsters always have some redeeming features.

The BFI Southbank menu really hits all the classic high spots. In addition to "Little Caesar," "The Public Enemy" and "Scarface," which speak for themselves, I'd strongly urge you to see:
--"Al Capone": another B-movie (and not very accurate at all), but featuring Rod Steiger's all-time greatest performance--and, considering his brilliant career, that's saying a lot. Capone or Capone-like characters have been played almost as often as Lincoln and Churchill, but no Capone will ever match the ferocity and conviction with which Steiger played him.

--"Lady in Red": One of Corman's masterpieces. If this is a B-movie, then it raised the bar 20 notches. Done with taste and verve. Look for Jack Nicholson in a bit part. Very fine performance by Ralph Meeker as Bugs Moran.