Violent games were ones that my brother and I played. Mortal Kombat II was our preferred choice.
On my own, I liked Doom and Doom II, so I guess I can't say what games parents think are alright for their kids to play.
Ratings are there for a reason though, so it's up to the parents to make the final call, especially on an M rated game. Thankfully, games rated AO are generally not sold on consoles or at retail stores, and they're usually PC exclusive.
Exception being Manhunt, but that's a unique circumstance.