I just scanned through the posts, so apologize if I'm just repeating information
First of I would consider going 3.1. Even start with a 3.0 and add a subwoofer later. If you want good sound for movies and tv, IMO, a center channel is more important than a sub. Second, if you have cable/satellite and any modern dvd/bd player, they are going to be able to output dolby and dts. Therefore, why not get an avr receiver that can decode these formats and manage these formats to a 3.1 (or higher) system?
For $1500 to $2K you can get a decent setup. Some people around here are happy with their sound bars. Some of these are powered, have wireless subs, easy hdmi connections and decode all the modern formats.
Cheers.