Ranger

Rangers are usually nature-loving fellas, wielding either a bow or two swords. They are patterned after a certain copyrighted hero from a certain copyrighted fantasy book. They are warriors that are generally useful for tracking down enemies. They also are shitty divine magic users.

In the 1st and 2nd editions of Dungeons and Dragons, rangers were not able to sneak or fight properly in chainmail or better, or shields either. Armor was so key in melee under these versions that this led to the popular party cry of "Ranger down!", heard during just about every battle. Rangers were thought to be the inspiration for the "At Death's Door" survival rule, since they would never survive a single session otherwise.

It is worth noting that one of the defining features of rangers is that they specialize in hunting down and killing members of specific races. From a pragmatic standpoint, this means they boil down to little more than racist serial killers who target by species. Being that race wars are one of the cornerstones of D&D, this is unsurprising. They are rendered irrelevant by druidzillas, because rangers just can't compete with a guy who can turn into a giant bear that shoots giant bears out of his eyes while farting lightning and mauling things with its own overpowered pet grizzly bear. Rangers can get a half-assed pet grizzly bear, but because their animal companions are only as good as a druid that has half as many levels as he does, it's half-assed.

In 4e they get to mark their enemies, making them useful when you're fighting one tough thing and a bit crap against swarms. They can either slaughter one enemy, or irritate several, depending on what the situation calls for. Or they can completely miss with their most powerful once-per-milestone attack, and that's some fun.