I always go to the Studios first but then I'm nuts about The Mummy. It can get quite crowded as can MIB, another favorite. I personally like the Studios way better but I don't ride the Hulk and so far no one will ride Dueling Dragons with me so once we ride Spiderman and Jurassic Park, we're pretty much done with crowded rides at IOA.
I don't think the order really matters though. Just whatever you're in the mood for first.