This from Kotaku review
http://kotaku.com/5944627/before-you-start-tips-for-playing-torchlight-ii-the-best-way?utm_campaign=socialflow_kotaku_twitter&utm_source=kotaku_twitter&utm_medium=socialflow

So happy to see the number of usable keys/slots
quote:
"Do Some Light Key Re-Mapping

This is just a personal thing, but I quickly remapped some of the keys to make the game easier to play. Specifically, I switched the potion hotkey from "Z" to "Q" and the mana potion hotkey from "X" to "W". I moved the weapon-switch to "E". That way, you can get potions off of the hotbar entirely and focus on using those ten slots for powers and pet power-ups. Also, don't forget that you have an alt-alt-fire on your mouse! You can set two powers to your right mouse-button, the second one is activated by holding down "Tab." Counting the mouse, you've got 13 assignable slots, more than enough for even the most overpowered adventurer."

The Torchlight 2 Armory Skill Calculator Plan ahead
http://torchlight2armory.com/skill-calc