I'm looking for some good, classic pre-printed adventures.

Something along the lines of Fallout. A bleak world, kind of thing. I want to adapt it and run it for a group of friends but I want to have a good base to work with before I branch out too much.

A good heist adventure would also be nice!

The Jewel of Yavin is a good heist adventure written for this game. Otherwise, I've found a lot of value in the old Traveller adventures. You can get these in PDF form from rpgnow.com.