If I were to summarize the basics of my understanding on this matter it would be as follows.
Direct damage spells don't scale with speed, but cast faster.
Spammable DoTs (like Haunt) don't scale with speed, but cast faster.
Always on DoTs (like the poison from a Gargantuan) do scale with speed.
Channeled spells (like Fire Bats) do scale with speed.
Summoned pets (like Zombie Dogs) do scale with speed.
I'm not exactly confident with this information, but it is the understanding I am currently running under.
edit: I think most of this actually comes from http://us.battle.net/d3/en/forum/topic/4...721?page=1 rather than the link I gave earlier. The one earlier I hadn't really read thoroughly, but just found. I think this is more the one that was really influential in my forming this understanding.
Direct damage spells don't scale with speed, but cast faster.
Spammable DoTs (like Haunt) don't scale with speed, but cast faster.
Always on DoTs (like the poison from a Gargantuan) do scale with speed.
Channeled spells (like Fire Bats) do scale with speed.
Summoned pets (like Zombie Dogs) do scale with speed.
I'm not exactly confident with this information, but it is the understanding I am currently running under.
edit: I think most of this actually comes from http://us.battle.net/d3/en/forum/topic/4...721?page=1 rather than the link I gave earlier. The one earlier I hadn't really read thoroughly, but just found. I think this is more the one that was really influential in my forming this understanding.