For the Punisher, anything by Garth Ennis. If it says "Max" on the cover, it will be incredibly grim and depressing, and very well-written. If it says "Marvel Knights" on the cover, it'll be pitch-black absurd humour and comedic ultra-violence, and very well-written.

(If you're going to try the Max version - whatever you do, don't start with The Slavers. Actually, it's best to start at the very start of that run, which if I remember correctly is called In The Beginning)