Istanbul has many events. Concerts and festivals will be organised by different companies. Madonna came to Istanbul for a huge party. The American metal group, Megadeth is coming to Turkey with new albums. (Start-end date: 19 June 2012-20 June 2012.)
You should see the historical peninsula, Princes Islands, Bosphorus, Beyoğlu. You must see;
You shouldn’t forget traditional flavers. (Simit, fruit syrup, raki-fish, lahmacun, kebabs etc.) and you should taste. The exquside flaver of kebab. Evey night is good in Istanbul. You can go to the Bosphorus country. (Ortaköy, Kuruçeşme, Bebek, Etiler.) You can spend many romantic moment while watching fireworks shows in the sky, after dancing. It is good idea. Kuruçeşme and Bebek have world famous bar and nightclubs. As the night ends you can drink a tripe soup joint :)
If you have free time, you can add the tours. (The Bosphorus Cruies, The Sultan’s Boats will astound you, Nostalgic Car Tour, Private Tours, Türkbalon.) Istanbul from the sky of Türkbalon.
In my opinion, Istanbul dreams of country. If you are rich, you can visit Istanbul.