Let me mention to the OP that Virgin America points transfer to Virgin Atlantic and Virgin Australia, so depending on where you want to go, you already have international flights covered.
Pretty much all the major brands, hotel and airline, now have a cc product that gives some type of loyalty bonus to big spenders. It's probably better to decide who you want to go with first, and then look at their product. You mentioned Starwood. SPG starpoints do have an advantage because they transfer to so many different airlines, but status doesn't transfer with the points.
(Note to the mods: this is the 4th new "my next card" thread in a day and a half. Consolidation?)