Evil for warmongerin', Good for buildin', Neutral for either, that's how I generally like to do it.
My favourite three are all evil: Dark Elves, Chaos, Orcs, for Sneaky, Spiky and Smashy.
Still, good/evil aren't all that black and white in WH, where everything's darker than generic tolkienesque fantasy. Take races that are traditionally 'good' in generic fantasy.In WH, High Elves are arrogant self-interested racists, vain and manipulative. Wood Elves are also racist and also unpredictably violent, sometimes killing human ramblers without warning, other times leaving them be. Dwarfs and Humans are more-or-less neutral in WH, having good and bad qualities like real-life humans, and being opposed to the likes of Chaos, Undead, Skaven and Orcs mainly because they are threats to their realms. Slann/Lizardmen are too inscrutable and mysterious to be anything other than neutral, IMO.
Undead, Skaven, Dark Elves and Chaos Dwarves can be seen as more or less evil. But Chaos is more crazy-obsessed than evil, and Orcs just like a good scrap.