what is your proceedure for setting up u'r system?

My experience suggests, that most people haven't a clue as to where to start, nor what they are doing, in setting up properly engineered audio/video system! At least, however, they might know what pieces of gear they want, but then have no idea how to implement what they end up with.
Anyone want to share their "thought processes" in setting up a multichannel HT/music system in a home environement?...what considerations do you take into acount?...what goals do you have with your gear/room?...where do the speakers/seats go?...how should I set up my processor?...acoustics?...tpes of gear?...system setup and lineconditioning?...why?...etc..