The Louis apartments are a nice place to stay in Santorini.
Louis (I never met Dimitris...) picked us up at the port and drove us to the apt., that was a big plus. Our room wasn't cleaned and ready when we arrived but they were working on it and we didn't have to wait too long. The pool is great and the place is right by the beach.
There is a market near the apartment with basic stuff.
It's also conveniently located by the airport which can be good if you are traveling by plane, although you do hear the planes every now and then.
It's best to rent a scooter to go around the island. Louis has a friend who rents them for a good deal.