Sub volume per movie?

[neos_peace]

Ok with income tax I'm going to be buying the Onkyo 805 very syked by this. Not 100% sure what sub I'm gonna get. Here's my question for you guru's out there. When you set up your HTS. How do you calibrate your sub to the best? And also, do you adjust the volume or the gain each time you pop in a new movie?

Ex: You adjust for say Drak Knight. Then when thats over you pop in Ironman. Do you adjust your sub for th ebest qaulity thump, or do you just leave it alone.

Basicly do you turn up or down for each movie or do you set it at one volume for al movbies. Personaly I find my self adjusting for every movie. Is that a good thing or doesn't really matter.

Please help I want to have a rockin system.