I just got back to playing after a couple of years, and I just noticed I never really knew what map to play. What are good maps for regular (not BGH money) 1v1's, 2v2's, and 3v3's?

Python for 1v1 or 2v2, Destination for 1v1, Blue Storm...
Pretty much all the maps the pros play. You can find most of the professional maps on the iCCup website.