I love Istanbul and travel to Dalyan sometimes . Eating fish sandwiches down by the Bosphorous river looking at all the mosques is magical ... or being invited into a shop for apple tea while they try and sell you a carpet ( I have 3 stored away in England ) . I always stay in Sultanahmet because it´s so central .... Istanbul is one city I would definitely consider living in . I have a friend ( Turkish ) whó lives there but would definitely like to meet you the next time I go .
I should also mention the hamam in Goçek ... superb .. and the trip around the islands in a big boat .. BBQ on the beach . What a great country ! I have had major problems there but they are anhialated by the good times .
The only downside to Madrid is the lack of a major river , the sea , a big lake etc... During summer that is a problem . The only resort is to go to the open air swimming pools , which are good BUT not quite the same .