If long haul travel was the only consideration, then Chicago is the best choice. But as others have said, *A is well connected in the USA. Pretty much any US/CO/UA hub with lots of international flights will do: PHL, ORD, SFO, IAD, IAH, EWR, and if you want to suffer one connection, any major city in the contiguous USA will do.
Living in COS, I can get to LAX, IAH, IAD, SFO, ORD in one flight, and only once have I had to deal with two domestic flights to get over a pond. And COS is hardly in a major city.
Last edited by mre5765; Aug 20, 2011 at 8:11 pm