Yamaha options
Chad, you have some good leads on your new system.
The Yamaha RX-V659 is probably the least expensive of their receivers with the Zone 2 feature you need. As you step of the broduct line, you will get more power and video features. With new models comming out next month (RX-V2700/1700). You should be able to get a good deal on a 1600 model in your $5-600 budget. You can always add a squeezebox3 or other device to deal with the music streaming from the PC.
If you want a warranty, order from an authorized dealer
If you are using a complicated distribution system like the Russound, you probably don't even need the Zone2/3 features on the receiver. The russound will loop multiple analog sources (CD, MP3, tuner, etc.) into the distrubution amp and use keypads to allow each room to select a different source. However, the Zone 2 and 3 are nice for a simple DIY house system.