One thing that I'd like to try that seems would be a lot easier was to divide every amount of experience by 10, and lower level-up expectations by the same amount. Second level would be 100 points, third 300, etc. Any system would be OK, though, as long as the level-up amount was an even number.
Another thing I'd like to try is to do away with level-ups and make xp points into spendables, a la Werewolf, Vampire, and the like. Or, maybe you could level up if you wanted, but it wouldn't get HP, BAB, etc., for it, but a +1 to each dice action. The option would be to get the +1 across the board for all of the xp you had(read as "amount needed to level up") or to spend them piecemeal on things like a better attack bonus/weapon skill, more HP, skill ranks, feats, etc.