Man I can't believe nobody thought of this sooner! (Myself included)
Demon's Souls
The combat is really good. Each weapon has pretty unique "weak" and "strong" attacks - whether it's a katana, longsword, polearm, large sword (claymore), pike, mace - they all have fairly different attacks and secondary attacks. Then you have shields - large shields have decent blocking abilites but are heavy, while smaller shields allow you to parry (as do some daggers and swords in your off-hand) and if you time your parry perfectly, it gives you a great stab opening for huge damage. Blocking, attacking, dodging, and running all drain you stamina so you need to gauge it just right. If you try blocking with low stamina it can open your guard similar to being parried and you can be murdered - although if it's PVP your opponent might be out of stamina from attacking and then neither of you can really do anything.
When your character is heavy from big armour and shields, you run slower and when you try a dodge roll you go "plunk" and get maybe half as far as a light charater. This creates an interesting dynamic.
I'm sure everyone's heard how hard Demon's Souls is, and a large part of it is figuring out how to fight properly. If anything it's almost too real in how it handles combat. But I really, really like it.