Got a better suggestion for 2006 than Gears? I fully admit in the OP that it's an odd choice.
Not really. I think Gears works fine simply because although PC's could have run it without breaking a sweat (which they did the following year), there wasn't really much that they actually had to run that year that was comparable. Oblivion and GRAW are the only other games that come to mind, and I'd probably still pick Gears over both of them.
The only year I have a real issue with is 2001. I don't think Wolfenstein even deserves a nomination here, let alone for it to have won that year. Both MGS2 and Halo destroy it imo, PC specs or not.
Some crappy examples there OP. Killzone 2 took a huge dump on Crysis when it came out, the lighting alone is a generation ahead, Uncharted 2 is no slouch either. Arma is demanding only it was badly coded and poorly optimized. Crysis 2 is another bad example, Killzone 3 raised the bar again and looked significantly better with larger levels and set pieces.
I'm glad Phediuk started this thread off and not you... holy shit...