Lanefan
Victoria Rules
In the very first reply in the thread, Raven Crowking got it right; at least for player characters. (one exception: I'd add a 16th "level", in effect a 0th-level for commoners, peasants, and so forth)15 levels.
1st level nobodies; 3rd level established in class; 6th level heroes; 10th level lords; 15th level epic.
NPCs should be able to be whatever level you want and the game needs to at least wave at rules for very high-level types for this purpose, but 15 is about all you really need for PCs.
As others have said, though, much depends on how long your players are willing to go between level bumps; and on how long you want the campaign to last. If you're looking at a 5-year campaign you'll have different perspectives on this than if you're planning a 6-month sprint.
Lan-"10 levels in 26 years"-efan