Sometimes there are really good works of which I'm not aware or have forgotten (not hard to do with my finely-honed "forgetter"!).
I'm asking this question of those who share my general theological persuasion, but the answer need not be limited to Reformed works.
And I realize that some could list hundreds of works, but please list the most important individual books or sets which you use.
Oh, yes, and the Bible is a given. 
Thanks for your input.