FYI if we're doing gestalt, I just prefer using the KISS method. Pick 2 classes. At each level gain both class features and whatever is better, period. So if you were fighter and wizard: d10 vs. d6(d4 if 3.5) hp, weapon / armor use profs as fighter, bonus fighter feat, bonus wizard feat, spellcasting, class skill as both fighter and wizard, good fort and will save, crappy reflex save, and so on. Note that you do not get the ability to ignore spell failure in armor as that is not a feature of either class. I also use elephant in the room feat taxes and every class gain 2 more skills as class skills. 8 am in the morning for me on a saturday is a bit rough. Is that the best time for everyone else? Also if we use PF for those who haven't one of the biggest difference is 1) no level adjustment 2) character class archetypes (they still have prestige classes) but archetypes replace certain class features and tweak a given class. Like if you wanted to wield big weapons as a fighter, you can do it with feats/race and also with a class archetype. Or both. ***EDIT Replying to Jess's note about 3.5/PF fusion. I also have no issues with folks who want to play a 3.5 character. There will be wrangling (like the skills Spot and Search and Listen is now just Perception) and where they are 3.5 and PF versions we'll usually go with the PF version (unless you really want your wizard to roll with d4 hit dice instead of d6). So bring on those reborn dragonborn whisper gnome dragonfire adepts...though I am a bit fuzzy with a lot of 3.5 since it has been a while. :)