One thing that all of us might want to keep in mind, though- d20 isn't meant for the experienced gamer. The idea behind 3rd ed. D&D, as I understand it, was to make D&D the "first game" again. D&D was the introduction for gaming to most of us back in the day, and Wizards wanted it to get back to that. They set out to make a game for novices, something simple and clear that people could learn easily. So, if it seems a little lacking to those of us that have been doing this for a while, it's because it's not meant for us, really.
Also, as inevitability pointed out, in a absolutely brilliant post, all gaming systems suck. But mine's better than yours, anyway.
On a personal level, I like it beacuse it IS so simple- The more crap a system makes me keep track of, the less I like it. Also- it got rid of every single thing that ever annoyed the hell out of me about D&D.
Besides, who the hell wants a system that's perfectly realistic, anyway? I have this thing called "real life" to deal with if I want that. A game is a fictional structure, and it's going to break down under too much "reality".
Speaking of which- Is it just me, or is the use of the word "realistic" in conjunction with gaming usually just shorthand for "I'm a Angry GM who wants to be able to kill my PCs easily?" Ah, but that's a whole other rant...
Anyway- systems are good, systems suck; both statements are true. I'm out.