Thanks for everyone's advice. Between CO, AMEX and Starwood, I have the ability to use a number of airlines. Being from northern NJ, CO usually works the best and is the only non-stop I'm aware of.

That said, do any of you know of other airlines that might be easier to deal with in terms of getting the confirmed upgrade immediately? The airlines that I can use are Northwest, US Air (Gold Elite), Delta (Gold Elite), America West and American.

Many thanks.