I plan to wait it out for several reasons:
I am the first order out of my dealer's four month allocation, which is completely spoken for. He also has a local waitlist of several people against his next allocation. If I were to cancel my order, I would move to the "back" of this line, and there is no telling how much longer the wait will then become. With the number of orders currently placed, I figure I could be adding many more months to an already years long wait.
I don't really find anything about the Solstice I currently have on order as lacking (hp, colors, options, etc.) I have spec'ed out the car with the options I want and have locked in a price that I can afford, at MSRP. Even if additional options became available, I probably wouldn't get them.
There's no guarantee against price gouging if I cancel my order and throw myself back into the pool.