I left my hearrrrrrttttttttt in San Fran-cisco......

I can't remember if I mentioned it already, but I plan on going to San Francisco for my birthday. I was checking the flights today, and it looks like I have a choice of stopovers*:

• Pittsburgh
• Philadelphia
• Charlotte Douglas
• Phoenix

Has anyone visited any of these airports before? Any preferences or recommendations? I'm thinking Phoenix, as I think it's the closest I'll get to visiting West Coast states for a while. I've done most of the East Coast already.

*I find it amusing that one can fly from San Francisco to London nonstop, but not from San Francisco to Hartford, CT.