This list consists of over 54% of the currently available Xbox 360 games released since the consoles' launch in 2005. While still quite a ways to go before completion, it is never-the-less a great start and helpful guide for everyone who is considering installing games to their Xbox 360 HDDs.
Green = load times improved by 6 or more seconds.
Yellow = load times improved by 3-5 seconds.
White = load times haven't changed, +/- 1-2 seconds.
Red = load times worse by 3 or more seconds.
Gray = game performance needs to be reported.
* = Japanese game.
NOTE: The above list has been compiled thanks to; CAG members, Anonymous tips, NeoGAF, AVForums, and StripesOnFire.