Agreed on questions about listening priority. If they don't care about HT or if they only want it for HT should be pretty well decided in their mind already.

However, if they really kinda want both and clearly aren't going to buy two separate systems to start with, then they should focus on the MC system just because it can be used for both. If they can't afford to do the whole thing right away, then I would generally encourage them to start with an AVR and the front speakers, then save up and add a center, then surrounds, then subwoofer.

While high end shows are all about 2-channel, I believe that most of the growth in hifi gear sales over the next few years will be in HT systems. All those people who now have large screen tv's are all prime candidates, and their desire for better sound is driven by movies. (the high cost of going out to the movies is helping drive this too) They will absolutely use their system for music, but it's secondary, and the key will really be that it's a living room system that the whole family uses and it's the only system they have. Creating gear that functions well for both will be more important than ever.