Sleep Easy is the best place to sleep if you want to be near almost everything you might think to visit on a short trip to Athens.
It's a couple of hundred meters away from the Monastiraki metro station, so you can get there straight from the airport. It's maybe 30 min walking away from the Acropolis slopes, and around there are hundreds of vibrant cafes, tavernas with great food, markets, and things to see ^^
We appreciated the comfort of having everything within walking distance. The neighbourhood might seem slightly unruly, but we experienced no issues.