I'm currently using the first rune of Poison Darts. It seems to work really well, and I've been using it since I got it, up to this moment during Nightmare Mode. For those who don't remember, this rune shoots three darts, doing 60% weapon damage as poison, per dart.
What I want to know is, what is the best attack that I can use to help me the most with all types of enemies?
I tried the exploding frogs one, but that wasn't too good.
"Best" is subjective since it is going to largely depend on the scenario. In general, against normal mobs in normal and nightmare mode all you want to do is rush into the fray and use Soul Harvest while spamming Acid Rain. Everything around you will die pretty instantly.
in Hell+ (and with certain Nightmare champions/elites/bosses) this is NOT advisable though. You will want to use a combination of Spirit Walk (with Honored Guest for mana regen), Dire Bats for damage, and Grasp of the Dead to keep enemies away from you while spamming Splintered Darts since it is virtually mana free.
"There is nothing good or bad, but thinking makes it so." ~ William Shakespeare
The Fire Bomb skill with the rune that makes it bounce to multiple target is almost like a fire-n-forget skill. My minions hold off the enemy while the multiple bouncing eventually kills the horde of monsters I encounter.
"You must gather your party before venturing forth" "Go for the eyes Boo! Go for the eyes!"
I'm in hell mode act III right now, and using firebomb with the +2 bounces rune and fire bats(dire bats) as secondary, with hex(jinx), spirit walk(jaunt), fetish army(reduced cooldown rune), and gargantuan(restless giant rune). Kicking a** and chewing bubblegum w/ this build