Actually, not much, if he uses a two-handed weapon, as the fighter gets an edge equal to half his Strength bonus. Assuming the 20th-level fighter above uses a greatsword, he deals 2d6+12 damage before other bonuses. The 20th-level monk deals 2d10+5 damage before other bonuses, so the fighter can still out-damage the monk on a per blow basis.Hussar said:And, keep in mind, that the monk is doing obscene damage with his bare hands. He doesn't need to burn feats or items to increase his damage, it happens as a class ability. What would it cost for a human fighter to keep up with the monk's base damage?
FireLance said:Well, some quick and dirty numbers for 10th level. Assume standard wealth value of 49,000 gp, of which about half is spent on offensive equipment.
Let's say the 10th-level monk has the following:
1. Strength 18 (starting Strength 14 and +4 girdle of giant strength: 16,000 gp)
2. +1 enhancement bonus from +1 amulet of mighty fists: 6,000 gp
His full attack with flurry of blows is +12/+12/+7
Let's say the 10th-level fighter has the following:
1. Strength 22 (starting Strength 16, 2 ability increases and +4 girdle of giant strength: 16,000 gp)
2. Weapon Focus and Greater Weapon Focus
4. +2 weapon: 8,000 gp
His full attack is +20/+15
A quick survey of the CR 10 creatures in the SRD gave me the following:
AC 28: Formian Myrmarch
AC 26: Adult White Dragon
AC 24: Juvenile Red Dragon, Gargantuan Monstrous Scorpion
AC 23: Fire Giant
AC 22: Bebilith, Clay Golem
AC 21: 11-Headed hydra
AC 18: Noble Salamander
AC 11: Colossal Animated Object
As expected, the monk fares comparatively poorly against the high-AC creatures such as the Formian Myrmarch and the Adult White Dragon, getting 0.55 hits per round of flurrying against the fighter's 1.05 hits per found of full attack against the Formian Myrmarch (about 52%) and 0.8 hits per round to the fighter's 1.25 hits per round against the Adult White Dragon (64%).
Against the middle range of AC between 24 and 21, the monk starts to catch up. He gets 1.1 hits per round against the fighter's 1.45 against AC 24 (about 76%) and 1.55 hits per round against the fighter's 1.7 against AC 21 (about 91%).
Against creatures like the Noble Salamander and the Colossal Animated Object, the monk actually gets in more hits on average, 2 hits per round against the fighter's 1.85 against the Noble Salamander (about 108%) and 2.75 hits per round against the fighter's 1.9 against the Colossal Animated Object (about 145%).
After all, he still has other abilities to compensate.
Klaus said:People get too hung up on the Amulet of Mighty Fists, when a monk's unarmed strike are "treated both as manufactured weapon and a natural weapon for the purpose of spells and effects that enhance or improve either manufactured or natural weapons *such as the magic fang and magic weapon spells)." (PHB, page 41).
Another thing to remember, is that the monk didn't pay for a magic suit of armor and a magic shield. True, he's prolly got a set of bracers of armor and the like, but, he's not out the money for those items either.
Mad Mac said:The Monk's unarmed strike has always been treated as a single weapon. Feel free to come up with crazy houserules to nerf the monk, but it's no use trying to use them as a debating point.
As far as what the monks abilities do with the exception of the odd ability like tongue of the Sun and Moon, the monks abilities generally serve to enhance his mobility and defense. Nothing wrong with that, in my book, it's just that the monk needs a bit more offense in his pocket in order to capitalize on being Mr. Survival Man. And I think it's a good think the class has those abilities.
If you just want to play a fighter who uses his bare hands, then I agree, you're better off making a fighter feat chain. A new class should have distinct abilities and feel, which the monks pulls off quite well. It's just a little weak, imo.

(Dungeons & Dragons)
Rulebook featuring "high magic" options, including a host of new spells.