The Salamander Synergy is a great rack system. I really like the infinitely adjustable shelf height (although the setup can be a bit time consuming).
As stated before they're not cheap.
The other thing is they are often a la carte, so be careful you know what you are ordering.
Oh, and they're not very deep, I think 18" on the regular back. Another 3-4" on the extended back. With your Marantz I'm guessing you'll need the extended back or just leave it off. I found out the hard way, but got a new receiver out of it.
They sell through Amazon and occasionally have good sales.
We also have a BDI AV Stand that is really well made too, just no where near as adjustable.
If cost is an issue try craigslist, especially for the synergy as you could add on later.