I would tend to Starwood because of Meridien and high quality European properties as well as pretty good coverage in the US. IHG would be my next choice because of the coverage for both Intercontinental and Holiday Inn. I am not a big fan of HI, wbut the coverage trumps some preferences. My third choice would be Hilton.

In your situation the Hyatt would be last because of their fairly spotty coverage everywhere. They are a very good choice if your travel includes their locations but it is essential to know you'll be travelling where they are.