Unfortunately, it doesn't look like much comes with this increase, other than the simple satisfaction that your experience points will continue to mean something after you reach Level 125 and beyond. Also, Reputation levels haven't been increased along with this, so you'll likely find yourself a bit "skewed" in that regard if you have already made it past Level 125. This is likely due to the fact that extra energy would be available to users daily who had a much higher reputation level, and we all know how the folks at Zynga feel about users having too much energy. If that happens to change in the future, we'll make sure to let you know, but for now, I wouldn't suggest holding your breath.
Are you a high-level player in CityVille? What level have you reached in your city? What other changes would you like to see made to the game? Sound off in the comments.