Actually, I would love to know what percentage of members here have two dedicated rooms... one for two channel and one for home theater, verses one room that serves both. I'm guessing that most are in the latter group, including myself but I might be surprised. And as you are starting to see, you have lots of options in putting your system together.
I started with a 'stereo' system in the 70's... once Lexicon brought out their first processor, I added it and some additional amps and speakers... then moved thru multiple processors and amps over the years but once I dug out all my old vinyl, I really started to focus on my two channel playback system. I decided to pull all my two channel sources off my AVP, and run them into a dedicated two channel preamp (with home theater bypass). That gives me a dedicated all analog two channel system with just my sources, my preamp, mono blocks, and main speakers (and soon, stereo subs). Then, if I want to watch TV, a BluRay disc, or something off of Roku, I just switch on my AVP (which in turn kicks on all the surround channel amps), and I put my dedicated preamp into bypass mode to share my front amps and speakers.
It seems like the best of both worlds, but my configuration also requires more rack space, more cabling, more power, more overall boxes, and likely, more money. Also, I think some of this depends on how much you like to mess around with this stuff. I will say that there have been times where I thought about just how much easier it would be to have everything run into one big box...
Good luck! Lots of wise people up here offering some great advice...