There's loads and loads to start from but rather than suggest individual titles try the following:
A good list might be to start looking at what the TCM channel plays -- you don't have to be a suscriber or even have TCM available -- just search its TV guide on the internet.
Other lists worth browsing are the listing from SKY TV's MGM HD channel and its own Classic Movies channel.
These are UK sites but accessible from the Internet at large. You probably won't be able to subscribe but their listings give you a great idea of what's available.
I have to say in passing that you really should look at these two 1) Forbidden Planet excellent THOUGHTFUL INTELLIGENT Science fiction and of course 2) the ORIGINAL version of "The Italian Job" -- all those Classic Mini cooper cars on the streets of Milan, the cockney voice of Michael Caine and an ending to DIE FOR -- brilliant all the way through.