Superman 64 was a great review, though IMO his best vidya review was the long and meandering retrospective on the classic Swordquest series. That said though, my favorite-ever video by him would have to be the third entry in his own spin-off series, Board James. It's also pretty short (under four minutes.)
It starts off pretty tame, with a concise introduction to the game and a rundown of its rules. Then his opponent rolls in, and shit genuinely hits the fan.
[video=youtube][/video]
Seriously, the climax would leave me slack-jawed with awe.