You could always play Rolemaster if you like simulation in your RPG's.
Rules for everything.
Dozens of spell lists that no player would ever use, or want to, but do reflect the integration of magic into the world setting.
Combat that is often deadly, messy, and unpredictable, but far more believable than D&D ever was.
Heavy armor causes you to be hit more often, but take far fewer and less severe criticals. Light or no armor made you hard to hit, but boy did it ever hurt when you someone landed a solid blow on you.
Difficult weapons have higher fumble ranges than simple ones (Flails were 1-7 fumble, daggers 1-2 on percentile dice).
Tons and tons of skills, with secondary skills and points that you spend just on those flavorful background skills and hobbies.
Healing requirements were incredibly specific, to the point where we hauled around an NPC healer just to patch us up. Someone severs your hand on a nasty critical? Get ready to channel your power points to the healer, cause honey, she's gonna need it. She will have to cast spells to repair the bone, nerves, muscles, and blood vessels, and perhaps the superficial damage as well (but that one I'd have to look up and I'm too lazy to get the books out of the basement).
Rolemaster used facing, parry, flanking with different bonuses for front flank, rear flank, and rear (hex grid).
The only thing it really lacked was targeted hits. You couldn't aim for a specific part of your foe - the crits come as they may.
It's very simulationist in ways - and more believable than D&D. There are critical results that say "You take a massive blow to your head. If you are wearing a helm, you are stunned no parry for 8 rounds. If you are not wearing a helm, you are dead." No one died from HP loss (although it was possible). Deaths are due to criticals and the nasty results. One of the spell crits read "Fetch a mop" after saying how thoroughly you obliterated your foe.
D&D has tried to reach a compromise, balancing playability with verisimilitude. Not everyone will agree on where that happy medium lies, which is why no one game system is ideal for everyone. Fortunately, the WotC ninja book recovery patrol has yet to sneak into my house to burn my Rolemaster, GURPS, 3.0, or 3.5 books. Yet.

Besides, I want to try 4E and see how we like it. We've got some novice players in our group who would run screaming out of the living room if we tried to explain Rolemaster to them.