Talent points are like a Diablo skill point in how you earn and spend them. (There are WoW skill points too and these are not the same thing!) However, you train basic skills, not learn them from talents. There are a few skills that come directly from talents, but most are augmentations of your character. +2% to your fire damage spells. 4% chance to avoid stuns, fears, and charms. 3 less rage (mana, sort of) to use the warrior Strike ability.
There is both a garrote and a backstab skill, however I forget exactly how the one in Diablo works. IIRC, the skill you might be thinking of is Eviscerate. Not that I played either a rogue or an assassin very far.
Only the exceptions can be exceptional.