Santorini in September
 

We're off to Santorini at the beginning of September, staying at the AVA hotel in Athens for three nights before flying to Santorini. In Santorini, we'll be at the Canaves Oia Suites for five nights. We've heard that Ambrosia restaurant has one of the best settings, but beyond that we are largely uninformed. So what we're looking for is recommendations of restaurants in both Athens and Santorini with particularly attractive settings (outside seating is preferred) and above average cuisine. I've reviewed Trip Advisor recommendations and find them a bit overwhelming. Suggestions, please.
Also, it appears that a rental car would be more convenient than using taxis or public transportation. If so, where is the best place to rent from? And what trips are worth taking?
For the most part, we're focused on just plain relaxing, but would be happy to get out and about for a change of pace and setting.

We did similar trip in October 2014 - great weather, BTW. We did not rent a car, just used pubic transit and walked. With 5 nights, you might want a car for a day or 2, not the whole trip.

Akrotiri Archaeological Site is a must see. We took a regular public bus there and back, it was very easy to do.

Museum of Prehistoric Thera - see this after Akrotiri. It's right in Fira, easy to walk to and small so you can see it in an hour or 2.

Do the The Fira to Oia walk

We had a nice dinner at: Aktaion in Firostefani - it is along the walkway. http://www.aktaionsantorini.com/index_en.html

Read this trip report, it has other areas on it, but it's really a good one.

http://www.fodors.com/community/euro...vilization.cfm

Ambrosia does indeed have a great location. I've never eaten there but I have read mixed reviews complaining about too-high prices and poorly-prepared food. I suppose this is inevitable for a "luxury" restaurant but it's something to consider. Also in Oia and near Canaves Oia is Feredini. Kastro is on the far end of Oia at the top of the steps leading down to Amoudi Bay and has a wonderful sunset view and I think the food there is excellent. Thalami, Strogili and Skala also sit on the cliff overlooking the caldera. Below Oia are the fish tavernas on the wharf in Amoudi Bay. Once you're there you'll be able to explore and choose for yourself. Menus are posted outside the restaurants.

Dining Athens:
ManiMani is excellent, no outdoor area, nice decor, wonderful dishes. Went there twice last trip to Athens.
A true neighborhood taverna in the upscale Kolonaki neighborhood, some outside tables, Loukianou,26
Some of the hotels have rooftop dining with Acropolis views such as Hotel Grande Bretagne, Electra Palace. There are others as well.

We had a nice dinner here, great views of Acropolis at night.
http://www.theacropolismuseum.gr/en/...afe-restaurant

Piu Verse about 20 minutes taxi ride off Athens city center might be a different option with no tourist on sight:
http://www.piuverde.com.gr/