New home theater network streaming suggestions?

[OrangeDriver]

Hey TH friends...I'm moving into a new home (house) within the next month or so, and it's going to be a much different situation than my previous apartment dwellings where my gaming PC has been directly connected to my TV and projector.

I'm looking for any recommendations (don't worry about budgeting/pricing stuff out) as to what additional components to buy to optimize my home theater experience.

What I own:
Non-smart 47" LG TV - going in the upstairs living room, preferably wall mounted with minimal clutter
Non-smart 720p Acer Projector - going in the basement
Onkyo 7.2 receiver and speakers/sub - going in the basment with the projector
Gaming Windows desktop with several large (1.5 - 2tb HDD's) - going in my office, but could split out HDD's to another dedicated build? I'm thinking I won't really want to have this always on.
1.5tb external hard drive
Asus router with a USB 3.0 port for network storage backups (do those REALLY work? never tried)

What I'm considering:
Soundbar/wireless subwoofer combo - upstairs living room
2 wireless devices that can stream from Plex? - one for TV and one for projector - not sure if a couple of Chromecasts would suffice or...?
Barebones HTPC to put my HDD's filled with movies/music into to be always on in a closet or something?

I dunno...I'm not sure what devices are best suited for low-touch streaming these days. I'm not a console guy, so don't bother with those. let me know if you have any thoughts!

 

[Wisecracker]

Not sure how big your media library is, but that USB port on your router with a 2TB HDD could hold hundreds of DVDs and a load of music ...

 

[OrangeDriver]

Not sure how big your media library is, but that USB port on your router with a 2TB HDD could hold hundreds of DVDs and a load of music ...

Yeah, I believe my media library is at a little under 2TB, but I'd like room to expand AND I haven't yet figured out if that is actually a solution for streaming from any device or just used as a backup. There's some weird proprietary backup software that comes with it, and I haven't seen anything in it about streaming/general use type of stuff. I may need to look more into it, but it kind of seemed like a junky/kitschy solution overall...? I dunno.