I know the feeling. First I received a depressingly fat envelope with two coupon books, 1 with 60 coupons for 5 years and another with 36, 8 years total.
So another big congrats from me.
My take: you will make changes, you will learn, technology will change, so start out simple, affordable, go from there.
Speakers: your main L/R need to create decent l/c/r imaging for 3 people wide on a sofa, so wide dispersion is important. Move off-center while auditioning.
I feel forever lucky I got these DBX Soundfield 100's that were designed to do that for video
http://www.hifi-classic.net/review/dbx-soundfield-100-135.html
You want your center just below the monitor to anchor dialog to the screen, so think that thru, pay attention to the base: legs, solid platform, wall mount. Once I had my center behind the monitor
Donna is short, I am tall, we messed about with the monitor on stacks of books until we found the height that worked for us both, not too high it hurts your neck, not too low that I was viewing thru the lower part of my progressive lenses.
Then I built a riser on top of the cabinet to support the monitor at that height and luckily when I changed my center speaker, it just fit in the riser's height.