White apes are one of my favourite monsters. They illicit a strong sword & sorcery vibe. If I make up the tower of a decadent wizard, odds are that I included a white ape inside as a guard. White apes are tough (HD 4) and quick (move 120') but they are fairly easy to hit (AC 6) and don't cause too much damage with their two attacks (1-4 each). They also have ranged attack - they may throw stones for 1d6 damage.
Another reason why I like them is that they are associated with Neanderthals which I also really like for their S&S vibe.