In picking the right combination of spells and runes, what is the maximum amount of arcane power that a wizard can have...?
The maximum Arcane Power for a Wizard is 185.
The base Arcane Power is 100. You can get 20 Arcane Power from each of Astral Presence (a passive skill) and Energy Armor with the Energy Tap rune, so +40 from skills giving us 140. Finally, you can get up to 15 Arcane Power (a perfect Mental affix) on each of an Orb, Wand and Wizard Hat, so another +45 for 185 in total.