My wife and I visited Istanbul from May 11th to 18th 2010. I had been before a couple of years ago and loved it and it's fair to say that my wife also fell in love with this great city.
We stayed at the Hotel Ipek Palas in Sirkeci, Sultanehmet and all main sites were walking distance from the hotel, such as, Topkapi Palace, Aya Sofya, The Blue Mosque, Basilica Cistern and the bustling port of Eminonu. We also walked to the Suleymaniye Mosque and the Grand and Spice Bazaars. Unfortunately, The Sulayminaye Mosque is undergoing restoration and is closed for 2010, but having visited it the last time I was in Istanbul, it is a beautiful mosque.
We also went on a day cruise of the Bosphorus for 25TL each. We bought our ticket from Eminonu and that is where we left from. We did the round trip which took an hour and half, and ended up at Anadolu Kavagi, where we spent around three hours having lunch and a 30-50 min walk up to view the ruins of a medieval castle, with an breathtaking view once you reach the top. This is a good alternative if you don't want to spend the 50TL price for the cruise, which you will find in hotel brochures.
We also took a tram to Kabatas to get to near the Dolmabache Palace, which, although we did not see from the inside, looked spectacular when we went past it on the cruise.
You need a good half day and some more for visiting the Topkapi Palace. Not all sections were open due again to renovations, however, we did see the Harem section and also the sacred relics section, which was a wonderful experience. To enter the palace cost 20TL each and the Harem cost an additional 15TL each.
We also caught the Tram to Istiklal Cadessi, the modern Istanbul, and although we walked to most sites, catching the tram was just as easy. This area was full of International high street and designer shops.
One of the evenings we went to see a performance of the Whirling Dervishes. Although we were really glad we went to see it, at 40TL each, it is may be a slight expensive as it was only for an hour.
Restaurants are plenty in Istanbul and we ate at Pasazade, which is Erboy Hotel's restaurant, and served delicious Ottoman style cuisine with excellent service. We also ate at Ozler restaurant, which was near our Hotel and our final meal was at the Aruna Cafe, which is under the Galata Bridge next to a whole host of other cafes and restaurants. Four of our evenings were spent at Aruna Cafe, where we would finish the day with a coffee and Nargileh (water pipe), taking in the view of the boats and feeling the wind of the Bosphorus river, as well as watching the beautiful Eminonu Mosque in front of us. We also ate at a couple of local restaurants/cafes, which may not have been as fancy, but were just as nice and much cheaper. Having read reviews on here and being warned on some restaurants charging extra, we experienced this only once where upon looking at our bill we were charged for expensive water, which was provided to us, not ordered by us.
People in Istanbul are very friendly, which enhances the experience and it is definitely a city we would like to visit again some day.
Apart from a couple of showers on one of the days, weather was brilliant; warm and sunny.