If Orb is your main skill it may be worth to Max CM, or at least pump it to a reasonable level to hit 27 or 32, if you have truly god gear.
Firewall for immunes
Teleport if you're poor and will MF a lot
Telekinesis+Energy Shield if you wanna play around or intend to go PvP.
Ice blast or Glacial Spike if you want a spamming spell.