I am currently using class variants (my setting has no arcane magic, so I am making use of the Divine Bard, and bolstering spellcaster options with the Cloisterd Cleric and Paladin of Freedom.
I also use Traits and Flaws.
Next, I am cnsidering getting a hex-based battle mat and using those rules, as they make diagnal movement easier to calculate. I am also considering implimenting Incantations, but not until the average party level gets into the double digits. (currently, the APL is 4).
Who else out there is mucking around with this stuff?