Question on home theater/music listening set up

Hey all! I am new to the forums. I was introduced by another member here and I have to say I am blown away by the amount of information on here. 

My question lies in the 7.1/7.2 surround sound systems. I will utilize my setup to watch movies, tv, and when I have the house to myself I love to put on some older 80's rock and sit and enjoy the setup. I love to dabble in classical music and for some strange reason I love horns. I am a big lord of the rings and game of thrones fan, and during battle scenes with drums, horns, ect I want to feel it in my soul haha. I love what I currently have, but I am trying to polish out what I have. I am open to suggestions on any brands that may go well with what I have now. My price point is primarily the used market. If you could just suggest the speakers you think would compliment the system I can attempt to find the best deal on those as possible. 

My current setup is as follows:

Speakers:
Polk Audio SDA-1A
Polk Audio SDA-2
Velodyne Minivee 8
Monitor Audio MR center channel

Receiver-
Denon AVR-3803

Power Conditioner-
Belkin AP41300-10

I have looked into ELAC, B&W, MIRAGE, PARADIGM, SVS, Ect trying to find something I like and I finally figured I should open it up to you amazing individuals to lend me a hand. 

Thank you in advance!