It may sound like a cop-out, but my answer is "all and none." I have played a ranger more than any other class in my 30+ years of D&D, so have a special love for the class. I have played a two-short sword wielding roguish hobgoblin, a classic elven archer, a scimitar-wielding desert nomad, and others besides. I like variations, not one d istinct or narrow archetype.
So while I facetiously cried fowl at [MENTION=1165](Psi)SeveredHead[/MENTION]'s view that the ranger is a background and not a class, I think there is some truth in that but ultimately disagree. The ranger is a template--broader than some (monk), narrower than others (fighter)--that allows for a range (no pun intended) of variatons within the template. When we get too focused on two or three archetypal themes, then we lose the potential of the class as a whole.
That said, there are some things I just wouldn't do with a ranger - wear heavy armor, for instance. I see a ranger as wearing no, light or occasionally medium armor. Weapons can range widely, but shouldn't impede movement. The main thing is that the ranger specializes in being in natural environments, whether forests, sub-arctic, deserts, or the Underdark. A ranger can be quasi-mystical, but doesn't have to be.
If fighter, wizard, rogue, and cleric are the core four, irreducible classes, then ranger is a close fifth, just ahead of paladin and druid, and then bard, monk, and the rest.