You are going to love Greece! Our honeymoon was 2 weeks, and it wasn't nearly long enough! We loved every second of it! We did 4 days in Athens, then hopped on a very small cruise/sail boat (WindStar, amazing!) and went island hopping (Rhodes, Santorini, Mykonos, Kusadasi, Bohdrum) and then ended up with 2 days in Bangladesh
4 days in Athens... Def go to all the touristy spots. One that we loved that wasn't very popular is Temple of Zeus. Very awesome! Omonia Square is awesome- some really great restaurants and bars/club type places. This is kind of a local hang-out. But don't worry, everyone speaks English.
Walk around the streets encircling the Pantheon- neat shopping and some cute cafes. Be careful of gypsies tho- seriously. If you've been to Europe before tho, you won't have a problem. We actually bought tickets to that 2 day hop on hop off bus tour thing- drove us all around town and was very neat, especially when you're hot and tired and want to just site-see a little
oh- one thing you must do is walk up Lykavittos Hill to the church on the top- absoutely amazing views! You'll go to Pyraeus eventually- but the view of it from here is amazing. There is a very expensive cafe up there- walk in, take a seat and grab a drink. Trust me, the price tag is worth it. Oh- and get Greek iced coffee- so good. Oh- and also, go to the bathroom in that cafe- its amazing! And you can take the trolly back down the hill(although steps are unavoidable)
Go to the Capitol Building! It was awesome! There were a few protests- but they were all peaceful. Know that protests over there are almost always planned and almost always peaceful. We only hear the bad stories over here. And you'll get to see the guards with the amazing shoes! their poofs weigh 3 pounds each!
Santorini is just okay in my opinion. We spent a day there. If you've never been to a touristy island, you'll like it- otherwise its exactly what you imagine(Capri is the same). The charm to it is staying at a romantic hotel and going out of the town a little. Take a trip to the town(cant remember the name) that's inland a little. Buy some wine here! Walk down the winding hill to the bottom of the island- and then take the trolley up. You could ride a donkey... but the walk is fun- and beautiful views. Go to cafes and just drink and talk and take in the view. Go to the monestary. Maybe rent a moped and drive around. Get a gyro. Eat some Greek food- even things you've never heard of, we fell in love with Greek cuisine! (not so much Turkish tho...). swim if you can, the water is so clear. Basically Santorini is an island to relax, drink some wine, and have sex