|The original cover.|
|Cover of later printings.|
The other TSR items I would definitely recommend for new DMs especially are the two early adventure modules B1: In Search of the Unknown and B2: The Keep on the Borderlands. Both have great advice and provide examples of what you can do in your games. Just don't assume they're the only way to play.
Non-TSR items would be a whole nother post I think. Maybe tomorrow.