Kurt Angle vs. Chris Benoit for the WWE title at the Royal Rumble, bar none. Not only is it my favorite Kurt Angle match, it's my favorite Chris Benoit match. Not only is it that but it's also my favorite match, ever. I love every second of it. Just so many awesome moments, reversals, and spots in the match.
Not counting that match, it's really hard to choose. Angle's had so many great matches. A few more between Benoit, his match against Shawn at Mania 21, his ironman match against Lesnar, his match against Lesnar at Mania XIX, his match against Eddie at Mania XX, are all amazing matches. I would probably put his Mania match against Shawn as his second greatest, with all things considered.