Receiver options
If having a single HDMI connection to the display is important to you, check out the Yamaha RX-V2600 or RX-V1600. You can find good deals on both now that the new 2700 and 1700 models are out.
Both will convert all video sources to HDMI and the 2600 will do upscalling to 720p, or 1080i. Based on the reviews, the receiver upscalling is not as good as many DVD players like the Oppo Digital.
The new and improved Yamaha RX-V2700 has a better uscalling chip but I haven't seen any reviews yet.
In terms of audio power and performance, an RX-V659 would have plenty for your Orb speakers, but you would need component video and 1 or more HDMI connections to the display.