Personally, I could probably deal with a few pages of clearly explained house rules, though there'd have to be a good reason to have them.
Let me add an addendum to that. I could most likely handle
more pages of house-rules if most of the rules consisted of added classes, removed classes, changed classes, or otherwise didn't rewrite the core system behind the game. If a person handed me a 50 page binder full of classes available, classes not available, new races, a tweaked magic system (everyone and their mother seemingly has one of these
), or other small details, I could probably handle it (assuming the DM knows his rules and could answer questions on the fly).
However, if someone handed me a 50 page binder full of house rules that completely changed the combat chapter, the skill system, and the leveling up process, I'd be much more wary.
As a DM, I try to use as few house rules as possible, namely because my players game to have fun, not to relearn a new set of rules for every campaign we play.