It might be the most boring gameplay for some, but it's just so damn effective that it makes it fun for me. There's also a good balance of risk-reward-ratio, which makes it enjoyable to use. After Zombie Bears, I really like Spirit Barrage (I often use them in same build).
My favorite damage spell however is Wall of Zombies - Pile On. Hilarious animation, insane spike damage. Too bad we can't use it as a "main damage source".
Dire Bats for sure. That's my right click and I use it as my primary. My left click is changing a lot in Inferno as I'm trying to find what works best with my build. When you get that attack speed up, Dire Bats can seriously start crapping down your enemy's throat.