Man, everybody's already named my favorite Karloff films... except one. How the Grinch Stole Christmas! And no I'm not being a smart ass. The 30's Raven is easy to find (you're of course talking about Carl Laemmle's with Lugosi and Karloff?) it's included in this DVD set for under $20.00.
http://www.deepdiscount.com/viewprod...ductId=5753151
A shame to buy a Lugosi collection for a Karloff movie though.