Hey Audioman,
I also own the 2500 and use it in a 2.1 setup. At the moment, I'm experimenting with the differnece in sound between the parametric equalizer and the tone controls. The YPAO setup uses both, which I'm kind of reluctant to use...I think using one or the other would be best, as far as electronics goes. But I also owned an older receiver before, and noticed that this new one is very transparent and has much different volume controls (ie, the -35db setting on the new one is much quieter than the -35db on the old one). I think that to get best sound from this machine, you would want to use it as a pre/pro connected to an external amplifier. To me, the sound is a little thin, and not nearly as dynamic as the local review says it is.
Hope it helps a little...