Yamaha RX-V2600
The new Yamaha RX-V2600 offers video upscalling from and deinterlacing for conversion of 480i or 480P to 720P or 1080i over the HDMI connection. I am not aware of any other receiver that offers this feature.
If you HDTV has a good scaller or if you already have a nice upconversion DVD player then this is probably a non-issue.