These are only suggestions of games that may challenge it, i'm not saying they will pass it:
- Gears of War 2 - The first one got a 94, so if they improve it it could get higher in the 90's
- Resistance 2 - A longshot considering the first one got an 86, but it could be a dramatic improvement
- Gran Turismo 5 - This series has a history of scoring 90's. Prologue got an 80 but only b/c it wasn't the full version
- Killzone 2 - Miracles can happen
- Final Fantasy 13 - I don't know what scores this series usually gets, but this game will be hyped
- Halo 4 - They obviously aren't making #3 the last in the series, its Xbox's big game.
- Little Big Planet - Could go either way really, but its a fresh new IP.
Thats about all i can think of. But i don't see any game passing it in the near future. The game with the best chance i'd say is GT5, it will have stunning graphics, great online, great gameplay/physics, etc. And will be the best driving game of all time.