[Calanor]

Originally posted by PvK:
It depends on the nature of the longer weapon. Yes, a pike has a signifigant minimum reach, but a two-handed sword, for example, can kill just as easily at shortsword range as it can at spear range.

Trying to get to dagger range is generally easier against a broadsword, than against a longer weapon.

PvK

A two-handed sword - provided that we are talking about the ones found in Europe during the late medieval period and early renaissance - won't fare that well at close range. A two-handed sword relies a whole lot on momentum and force, which is hard to achieve if someone's a few inches away from you considering the great length of these blades. The edge wasn't that sharp, as it was mainly meant to penetrate armor (hello, Saber Cherry!). Again, I am refering to Western two-handers here. Eastern (Chinese, to be specific) two-handed swords tended to be much shorter, more akin to the Western "hand-and-a-half", and were used in quite a different manner.
Of course, there are always exceptions, but I think the above is true in most cases.