The Yamaha 1500 & 2500 both have zone 2 (and zone 3) capability. The 2500 includes amplified zone 2 (not sure about the 1500). The second zone is truly discrete, in that you can listen to something completely different in the den while watching a movie in the theater.
You can also use the zone 3 to feed a house system if you wanted to.
I will likely get the 2500 - zone1 = theater zone2=master bedroom zone3=whole house feed for FM.
OF PARTICULAR INTEREST: Many receivers advertise zone2, but do not handle it very well. That is, you try to turn on zone2, and it also turns on zone1. Or you MUST use the rear IR input to control zone2. Or if zone1 is using the FM radio, then zone2 has no control over it. The Yamaha offers true discrete control of zone2 separate from zone1. This way when you want the theater off - it is off and the den can be on. When you want the theater on, the den can be off. But, pull out the remote, and turn the den on at any point - it won't mess with the theater at all.