I think now Qatar on the Top, while Saudi and UAE will stay on top comparing to the number of open projects in all fields specially the construction and Healthcare.
Doha in Qatar and Arbeel in Iraq (Kurdustan) are lately the most booming cities. Both are working on huge scale projects and constructions, starting with urban planning, highways, bridges and tunnels, towers and hotels,residential buildings...etc.
Doha is a new version of Dubai, Arbeel is a virgin city with lots of investments.