Approach on picking the right speakers...

[ascotinmpls]

Hey all,

I'm in the process of buying a new house which will have a dedicated space for movies/gaming. I have a setup in my current place which i never really put any thought into. I just bought speakers and a subwoofer based on seeing a deal on Amazon or at Best Buy.

Anyway, for the new house i have the wife's approval to upgrade the setup. I'm looking for any advice on how i should be picking my new speakers and subwoofer(s). I assume that actually listening in a showroom is the best situation but are there any methods that can be used for buying based upon specs? Does receiver specs matter in that situation?

My current setup is:
Receiver: Onkyo TX-SR508
Bookshelf's: 2 x Polk T15's
Center: Polk CS10
Subwoofer: PSW10
Surrounds: 4 x Insignia NS-SP213

So far, for the new setup i have:
Receiver: Denon AVR-S710W

I'm planning on setting up with 5.2.2 to take advantage of the Atmos/DTS:X that the receiver can handle. Any thoughts or recommendations on how to best pick speakers for either buying or test driving?