A nice flat in the heart of Porto. We basically could walk the main parts of the inner city by foot from there and also by metro it is very easy to get around and reach any point.
Make sure to close the window lids in the morning before you head out for the day as the sun shines in directly in the afternoon until the evening.
The cobble stone street up the hill and the plaza in front of the apartment tend to be quite noisy (especially on the weekend), but if you don't plan to go to bed before 11pm it is a great place to be.