Well, I'm now settled on Warm 2 with the G10 in Custom and Game. However, it's my opinion that THX still benefits from the Warm 1 temperature as I still notice a yellow sheen over just about everything. At any rate, Warm 2 provides a slightly more natural looking green, much more natural looking skin tones, (especially pale ones) and an overall more saturated looking color pallet. Warm 1 helps blues pop a bit better in some animated content and films with aquatic scenes, but that's it. The only content that I demoed that I decisively liked Warm 1 for was Chicken Little (terrible movie, great demo material) due to the brighter looking sky. Warm 2, however, won out in every other test.
I watched Quantum of Solace a few days ago under Warm 1 and decided to watch it again as it would still be fresh in my mind. I immediately noticed a difference. Bond's rugged mug during the opening showed much greater depth and detail while M's fair complexion lost all of the blue that I noticed in the previous viewing. Also, the actors didn't drown in the sea of white that is the set for the office/headquarters scenes and lighter architecture looked decidedly more realistic. I also viewed a few clips of other live action content like Man on Fire, I, Robot, and American History X. All gained an added amount of realism on all skin tones under Warm 2 and trees, brush, and grass all looked a shade deeper.
As far as animated content is concerned, I watched clips from Cars, Madagascar 2, Bolt, and Kung Fu Panda. Again, everything looked fantastic and the shade of yellow looked decidedly better under Warm 2. Lightning McQueen looked perfectly uniform with the rest of the scene, Alex the lion didn't change to Hellboy red, Melman the giraffe gained a bit of punch, and Mantis/Viper looked fantastic. Blue skies didn't look too quelled and white characters like Bolt, Po, and Marty looked white, not yellow. (and I was intentionally looking for this) As mentioned previously, the only content that I preferred under Warm 1 was the overly-saturated blue sky in Chicken Little, but it didn't look bad under Warm 2 by any stretch.
As a final test, I took a look at Sin City to see if it would come off as yellow. Surprisingly, if it looked any color it was slightly blue, but all was well.