I agree with Karl (and Peter Thiel, as reported by Jessica Stillman on Inc, see quote below)
"Be a Delaware C Corp
No if, ands or buts about it. "A very important preliminary question is how you should set up your company. This isn’t a hard question. You should set up as a Delaware C corporation. That is the right answer," insists Thiel. This separates your business and personal affairs, offers flexibility when it comes to issuing stock, and makes it possible to exit the business by going public. "The big disadvantage for C corps is double taxation," but the advantages outweigh this problem."
If you click around you can probably find his lecture series online (Blake Masters recorded and posted them) or his book Zero to One is worth a read.
If you find that Europe becomes a significant market the UK is a very friendly environment (and corporate tax is going to fall to 20% from 1st April). If you want an English language location with good incentives for inward investment, a strong tech community in the Euro zone, then look at Ireland.