ok, well thanks for the comments. I thought I understood everything, at least before when I was only looking at my individual program I am on, with United Airlines. Maybe it is because I booked a FF ticket to China (with a friend's miles) but the system seems infinitely easier with more international options than with other airlines...even with others from the *A. I have no idea why that is the case though.

I understand the concept now totally about not being able to transfer miles from one to another, like say from Turkish Airlines to United.

But, one thing I don't understand is this: I want to book a hypothetical trip from Charlotte, North Carolina to Vientaine, Laos. United seems to allow me to do this without any problems, on their website. When I tried to do the same trip on US Airways, it didnt allow it, but United and US Airways are part of the same alliance, so why did US Airways give me trouble? Of course, this is all academic now since I am already part of United.

I enjoy traveling to Asia, and it seems like a good way to get more use out of miles is to book a flight to a smaller town you want to see (such as Kashgar, China) if you want to see that area of China, instead of simply booking it to Beijing, China and then getting to the smaller city on your own. So, the 32,500 mile for a one-way ticket from Charlotte to say Kashgar or Vietaine seems to be a good value, especially since US Airways (and also American Airlines) did not allow me to book the hypothetical trip.

I am assuming most of you only have ONE carrier you primarily use, right? In other words, it isnt worth it to get a FF card to cover United, American, and US Airways...or is it?

For what it is worth, my current plan is to keep United, use my HH points for some hotels since I need hotels anyway. The SPG card was intended to be dumped in a 1:2 ratio to the United account, but perhaps the best usage out of the SPG card is to keep it to get a few hotel stays.