Hehe, coming out of lurking to post on this thread...
I don't play D&D exclusively, though it's probably the one I play the most. Well, I don't play much at all actually, I just DM most of the time, so we experience with different games rarely has a player's perspective to it. At the moment, I am massively frustrated with how rigidly everything is defined in the D&D universe, and how generic the flavour is.
I started adding houserules when I didn't like the flavour. The more I looked into it, the more I started modifying. It got to be rediculous after a while, my list of changes is huge, so at the moment I'm taking all my changes and compliling them into a setting, and giving the option to any group I DM to either choose my homebrew if they like it, or just have me run a rules as written game. Optimally, I'd run my own homebrew, but I can understand a player's reluctance to jump into a setting they don't think is good fantasy. People have often characterized my justifications for my changes as odd.
I haven't ran a game since I've started modifying the system, but I never did stick to the rules for handling things. I tend to run very loose games, I freeform combat when I don't think rolling is neccesary, I'll bend limitations when I feel it would be fun to do so, I make up magical effects without codifying them into spells, let player mix/max to their heart's content and generally make life hell for any rules lawyer in my game.
I suppose on that note if I ran my homebrew, you'd be hard pressed to call it D&D, though to be fair it's not like I radically changed character creation or combat.
