ROI. Where is money better spent?

Balanced components negate the need to some extent for jumping into the cable scramble. That's no small blessing. 
A setup guy I know with many years of experience tried Belkin XLRs across the room and wasn't sure there was much difference.

Balanced components negate the need to some extent for jumping into the cable scramble. That's no small blessing. 
A setup guy I know with many years of experience tried Belkin XLRs across the room and wasn't sure there was much difference.
Room treatment takes time IMO and there is no substitute for sitting and listening a few times to evaluate the effect. Personally I get the pre and play with the room indefinitely. Getting the reverb time down incrementally keeps you from going overboard on this and you have opportunities to sit and listen to the equipment as a bonus.

Room treatment vs. speakers is kind of a chicken and egg.

Good room treatment makes a room more speaker and sub, and genre and movie friendly. However you don't really know what the problems are until you get speakers. :)  I will say that once you have good room treatment you will swap a lot of things except them. :)

Best,

Erik

Cables make a difference but the preamp is the most important piece to get right. Get the best preamp you can afford. If you have cables you can sell so you can spend more on the preamp, do that too. 

If you screw up on your preamp, you'll be spending a ton of money on cables to try and fix your mistake. It won't work, of course, so you might as well just do it right the first time.