Great Room Sound System

Hello AVS community.

I have a great room that is open with the kitchen and dining area which is about 600 sq ft. I would like to get a good sound system for my entertainment needs. The use of this system will be for HD movies and listening to music, I rarely watch cable TV. I recently purchase a Harman Kardon - AVR 1700 which Best Buy had on sale for $200. Excuse my terminology and knowledge on this because I do not know much about home theater systems. What speakers and subs are recommended, wall mount or floor speakers? Is having 5.1 or 7.1 surround sound that big of a deal. Another idea to the sound system I had was to also install in ceiling speakers throughout the whole house but I didn't know if that was a good idea or not. If you could please help point me in the right direction that would be much appreciated. Also I have nothing but tile, wood laminate floors, and vaulted ceilings in the house if that matters.

Thanks for your time

Thanks for the reply. I attached some photos of the room. As for the price... I haven't set one yet. If I think it's worth it I'll pay for it, but to start off I would like to keep it under $2000?

First photo is the great room. Behind that is the dining area and to your right is the kitchen with a bar height counter.

Furniture is another project I'm working on but I know furniture so no worries there. The interior is still being worked on so I haven't moved anything in.

Thanks for the suggestions. I'll look into those system. If there are other setups worth looking at I would like to hear them. I could move the budgets up to $3k or more.

Thanks again.

As of right now I am going with a HSU system. Got in contact with them to see which one they recommend. I was looking at the Ultra15 5.1.