No HBO? Why have a dvr?
If you have the free On Demand channels, be sure to check them out. Older popular series episodes can be viewed there, and most new ones will be availible the day after they premier. It will save a lot of space on your dvr.
There are a lot of good dramas, but you will need to catch the earlier episodes first to catch up or you will be lost. Foremost is BREAKING BAD, also SONS OF ANARCHY, MAD MEN, RESCUE ME...