While the legitimacy of Vitor Belfort's shot at the title has come into question, the fight has been booked as the main event for the UFC's Super Bowl weekend card. Assuming Anderson is able to win that fight, rematches against his most recent loss (albeit DQ) in Yushin Okami and his most recent almost loss in Chael Sonnen await.
Dana White has not been opposed to reneging on number one contender matches. Furthermore, while it would be easy to promote the Sonnen rematch, there has been significantly less clamoring for the potential Okami rematch. If Anderson Silva is still the middleweight champ after UFC 126, summer 2011 might be the perfect time for a superfight.
If not against GSP, I would love to see Anderson in some type of division-crossing champion vs. champion superfight before he retires (even if it's not next summer).
With all of this in mind, I would like to know which Anderson Silva fight, at this moment, you would most like to see.