3.5 advice requested

[Telonius]

So far I haven't had to deal with any gamebreakers. I generally work at it two ways: in character and out of character, both through house rules.

First, nerf the over-powered. DMM doesn't exist, specific egregious spells and feat combinations are banned, all Druids are shapeshift, among other things.

Then, bump up the less powerful. Monks get a significant power boost, Dungeoncrasher is encouraged, Ranger steals the Druid's companion, ToB is allowed, Half-Orcs lose the Charisma penalty, Half-Elves choose either the feat or the extra skill points, etc.

Finally, tie up the loose ends in-character. In my games, Pun-Pun has already ascended, and is the over-deity of the universe. Since he has an arbitrary amount of wisdom, he's realized that he's a fictional character in a game, and is having fun just playing along. He'll personally prevent any character from using an overpowered ability. If he has to, he'll dispense a Phylactery of Brokenness (shaped like a little cheese wheel) to people who skirt the line. (I've never had to take this step, but it's in reserve if I need it).

EDIT: Forgot the most important thing - I make absolutely sure that the players are aware of this stuff at the outset. First session of the game, I take a little time to make sure everybody knows it, and everybody knows that the whole gaming group knows it.