Which AV Receiver?


Hi,

I have a pair of Klipsch RP-8000F floorstanding speakers.
I am a little unclear about what I need to complete my setup.
I want to use these as home theatre speakers when watching Netflix or Satellite TV, and also as music speakers when playing off Spotify through the TV or via iPhone. 

The guys in the Amp forum recommended an AV Receiver but I don’t know anything about AV Receivers.
Are they able to power the speakers and bring out the best in them? I heard Denon, Onkyo, Marantz, are all good brands. Perhaps you can suggest a few models ranging from 300-1000 in price. 

I need enough channels to add in a sub (I have Klipsch R-12SW) and potentially a center speaker (yet to buy but probably will get the Klipsch RP-504C) at a later stage. 
I am a newbie to all of this so willing to learn, please forgive my lack of knowledge.

If you need more information please let me know. 
Many thanks in advance!
laher
Thanks.

Is it worth going for the new Denon AVR-X2600H. I’m UK based by the way. I can get this one for £499.

Is this powerful enough for my Klipsch towers? Or should I look at a higher end receiver?
Get the AVR-X2600H. Plenty of power! No problem with driving your Klipsch speakers! Spending more (2X, 3X, 4X...) will not get "better" sound! Like I’ve said get a smaller pair of Klipsch speakers for the rear. No need for a center speaker (will only degrade the sound). 
Thanks for your advice roberjerman. 
I will leave the center speak and rears for now and set up the towers and sub with the X2600H.

When I’m ready I’ll do the rears instead of the center. Or is it worth adding both? And yes, will probably get RP series.

Out of curiosity, what will 2x, 3x, 4x get me on the AV receiver?