Capital of the Middle East

What city would be the capital of the Middle East?  These are the 20 countries covered by the US Central Command: Afghanistan, Bahrain, Egypt, Iran, Iraq, Jordan, Kazakhstan, Kuwait, Kyrgyzstan, Lebanon, Oman, Pakistan, Qatar, Saudi Arabia, Syria, Tajikistan, Turkmenistan, United Arab Emirates (UAE), Uzbekistan, and Yemen.  I'm not sure the former Soviet countries should be here, and Turkey should perhaps be included.

These are the candidates:
1.  Cairo, Egypt.  The Cairo metropolitan area has more than 15 million people and is the 16th largest in the world.  Egypt is too politically unstable to serve as a regional capital, although the Arab League has its capital in Cairo.
2.  Dubai, UAE. The Dubai-Sharjan-Ajman conurbation has more then 3 million people, and has a GDP of more than $100 billion/year.  The tallest building in the world is located here.  Dubai is rated as an Alpha+ global city.  It has the 6th busiest airport in the world.  The nearby port of Jebel Ali is the 9th busiest, and recent expansions will make it the world's largest.
3. Abu Dhabi, UAE. Abu Dhabi has less than 1 million residents, but it is the capital of the UAE, and accounts for more than 50% of its GDP because of its oil wealth.
4. Beirut, Lebanon. From the 1950s to the 1970s, Beirut was "the hub of economic, social, intellectual, and cultural life in the Middle East", and Beirut became an established banking center for Arab wealth. However, it was severely damaged by the Lebanese civil war, which ended in 1990.  It is one of the top 10 cities in the world for tourism.
5. Doha, Qatar.  Qatar has the world's highest GDP per capital.  It hosts the Forward Headquarters of the US Central Command.  It will host the 2022 World Cup (soccer).
6. Riyadh, Saudi Arabia. Headquarters of the Gulf Cooperation Council.  Capital of Saudi Arabia, and the largest city.

And the winner is ... Dubai.

Edit: What about Istanbul?