If you are going sightseeing, the queues to get tickets into the Acropolis can be mad. It costs €20 to get in there, and for €30 you can get a ticket that allows you into 6 attractions around Athens (including the Acropolis). Go to one of the other sites and get the ticket there. Even if you don't look at any of the other sites it is worth the extra €10 to skip the queues!
The area we stayed in is called Gazi, lots of pubs and clubs there so it is a good place to head for food and a night out. It is a little bit away from tourist central but still walkable. There is a exhibit space in the middle of this area, which is where the gas works used to be. Lovely place to walk around and grab a drink.
These are the two nicest places we ate
Butcher & Sardelles
http://www.hellenicfood.gr/
Lovely, but quite pricey
Seychelles
http://www.seycheles.gr/el?utm_source=tripadvisor&utm_medium=referral
This was the best meal we had in Athens. Very hipster, the waiter's beards were a sight to behold! I can deal with that when the food is good though.
The underground station for Gazi is Keramikos. The underground station brings you right to the old gas works.
