At these prices, you have certainly met diminishing returns.
So, I must assume that you will be planning to spend a proportionate amount of $ on acoustic room treatments and measurement gear too? If that isn't in the plan, then you would be better served to skim some of those $ off of the generous electronics budget and add it to room treatments and measurement gear.
These are simple economic concepts (not limited to AV), when you hit diminishing returns in 1 area, you get the most bang for the buck with the first few $ that you spend in other areas that have not begun to approach diminishing returns.
Personally, more than ~$2k for a pre-pro is getting to be a bit silly to me, for my wants and needs. Really, it's the fact that a pre-pro is the gear that tends to go obsolete the quickest. A good power amp pretty much never goes obsolete, same for speakers, so more $ there makes more sense to me, and I feel like I have been getting good returns on the TV technology if it is at least 1080p (depending on a few factors, etc). And, since speakers are the only transducers in the signal chain, it makes sense to spend the big $ there.