Sounds like a pretty logical roadmap to me. So, this year, and very soon, my purchase list might look something like this?
1. New deck w/cabin control
2. 5 channel amp
3. 6 new in-cabin speakers
4. Possibly add a sub with enclosure

I'm okay with all of the above going over $1000 as it looks like I will be doing this in stages.

Next year I can then focus on the tower system. So, if the above list is a good starting point, what products would some of you recommend?