Coutu is probably up there, for one night of assaulting two refs.
Dirty is relative, if he did something to your guy, it's a thousand times worse then if it's to someone else. I will give full acknowledgement to players like Bertuzzi and Cooke, although I always thought May and Ruutu were dirtier, they just didn't go out with intent to injure every time (Cooke) or have a massive, massive dirty play (Bertuzzi).
I've heard Aaron Rome's name come up in conversation for what he did to Horton. In the same way, based on that and Bertuzzi, I consider Keith a dirty player for his elbow to Daniel. I consider Ohlund a righteously dirty player for breaking Koivu's leg with a slash for having the same situation as Keith alleged (constant borderline elbows in scrums).
McSorely and Simon there too, remember the 90's/early 2000's?
Going back further is more then I can do,but Coutu was banned for life, and Simon was effectively labelled too high a risk to play after his last two suspensions, so as far as metrics go, I'd say either way.
I totally forgot some of these too:
http://www.theglobeandmail.com/sports/hockey/the-longest-suspensions-in-nhl-history/article4101583/