|Barbarian, Unearthed Arcana.|
Splatbooks? Hmm, that would be most books after the core rules, right? You could call the Best of Dragon IV (which I mentioned in the previous post) a splatbook. It has enough classes to fill a sandbox: Bandit, Bounty Hunter, Cloistered Cleric, Death Master, Duelist, Jester, Scribe, Smith... plenty of player choice for a campaign, even if they're meant as NPCs. Plus there's also the whole Half-Ogre! I rolled one up (as an NPC) as soon as I saw that lovely Elmore artwork.
Any of those early RPG magazines, like Dragon and White Dwarf, just oozed creative campaign balance-tipping potential. The sort of potential that would later become authorised in TSR books and modules.
Unearthed Arcana? There's some serious * in there! That would be the first book I bought that introduced a whole lot of fluff to our game. Serious, game-changing fluff. The sort of fluff that was now officially optional, as opposed to experimentally optional.
It would be fair to say that my views of their worth has changed with time. However, my first splatbook approved character was a Wu Jen from Oriental Adventures. That was long after playing alongside Barbarians, Cavaliers and Rangers (with weapon specialisation: bow), knowing that the old standard Fighters were now the poorer class choice. Can't beat 'em? Join 'em! For better or worse.