I finally had a chance to hook up my Nintendo Wii system to the Yamaha 765. The Yamaha RXV-765 is equipped with the Anchor Bay ABT-2010 scaler. This scaler is the same one used in the 2009 Denon line of receivers, and is highly regarded. Although I am only using a composite cable for now, and my tv is only capable of 720P, there is a noticeable improvement in the picture quality. There is less artifacting and mosquito noise in the general scene, and text is rendered with more blending and less jaggies (what I call jagged lines that don't appear smooth). Both problems are typical of composite video connections, and are handled nicely by the scaler.
Most of the games I like to play on the Nintendo Wii are high frame rate, very busy scenes with a lot of fast motion graphics, games like Super smash brothers brawl, and Mario Kart racing. So, as a result, the picture quality during game play is not as easy to see the improvements in as when viewing a static screen, or any of the RPG games that there are not so many objects rendered.
Overall, I am pleased with the picture quality produced by the Anchor Bay scaler. Especially on a composite connection using only the stock average quality cables provided by Nintendo. I could only imagine that feeding the scaler in the Yamaha RXV-765 a cleaner signal would result in an even bigger improvement in upscaling picture quality that would really show the quality of the Anchor Bay scaler solution.