I think I have discovered why it takes my paintings so long to dry - in a discussion I had this afternoon with a clerk at the art supply store I go to, the man mentioned that linseed oil will lengthen drying time. So in this piece I am using less oil than I typically would, and so far so good. Hopefully it will be dry enough for me to make further progress on it in the morning.
Last month I shelled out a huge chunk of change to upgrade from student oils to artist quality oils and painting mediums (rembrandt, old holland) and the difference is pretty remarkable. I would highly recommend to anyone who has been avoiding artist quality paints because of the price to just give it a shot with the one or two colors you tend to use most. I swear you'll never be cheap again.