Gilin, Invisible Blade

Invisible Blades are unusual fighters (usually of some confidence or flair) who see that the key to success in combat is not always through big muscles, weapons or spells. Wielding only knives and other small, unassuming weapons, an Invisible Blade relishes being underestimated. He boldly takes on foes, unarmoured, eager to take advantage of their overconfidence, then feints to create an opening and guts them before they have a chance to react.

A more common class choice for the smaller, nimbler races, this prestige class (a class only useable when certain skill conditions have been met) seems to have been built to give Rogues the opportunity for a more in-your-face play style. To the common thug, a dagger obviously does a lot less damage than a longsword - however, Rogues who attack their opponents from behind or catch them off guard get a huge "sneak attack" bonus (hahaha). Invisible Blades, as well as being able to add their intelligence bonus to their AC (to help them out with the whole "not wearing armour" thing) get a better feint, which essentially allows them to sneak attack people from the front.

I'm a huge fan of the idea of classes not being cut-and-paste character types - obviously generalising, whilst fairly safe at first, gets boring quickly. I love prestige classes because they help you specialise your character into a real niche. Not all rogues are the same - a player might want to roll a Rogue who can sneak around like a ninja, or who can fight using spectacular acrobatics, or uses his fists like a street brawler; prestige classes give you further bonuses to help you make those play styles viable. Blanca once wrote a really cool NPC Rogue who was dead shot with a bow (ranged sneak attack, anyone? okay okay enough with the tf2 metaphors). So, yeah. If you like your rogues showoffish and bluffy, the Invisible Blade might be for you.