I'd play evil if I chose an anti-villain character, or even anti-hero. But even then, I'd have a theme or story I'm sticking to.
e.g.
One flavour of anti-hero fallen paladin, say disillusioned over druid indifference to Tiefling plight, is no longer satisfied with eventual comeuppance - payback has to be now and immediate. This play through skirts evil and may even have kind streaks and guilt runs.
But if I play a supremely ambitious wizard (anti-villain) who'd sacrifice almost anything for longevity and arcane power, I'd have him view everyone fundamentally as objects to be used, avoided, or eliminated on way to such ending. For this playthrough I would beeline to ending so as to emphasize treating every choice as opportunity for cold intellect decision making. Even so, might still have some sentimentality like a romance partner to complicate playthrough decision making - and maybe make the coldest decision at the end, or the one redeeming weakness.
