My votes.. /Fire for AoE goodness.. enjoy the aggo you create 
, /Mental which I enjoyed very much on my Rad/Blaster, /Elec and /Nrg because you can never go wrong with those...
The hard things I can do--- The impossible just take a little bit longer.
If numbers are so much more important than a teammate who is fun to play with, forget about the game altogether and go play with a calculator instead. -Claws and Effect-
I pretty much agree.
Radiation/Fire has lots of close area attacks.
Radiation/Mental has 3 ranged area attacks and two close ones.
Radiation/Energy allows for some nice stun stacking (fingers crossed, its my latest project)
What are the best secondaries for Radiation? I see some references for Rad/Ele and Rad/fire but are there no other secondaries that are viable?
Personally I'm curious if rad/ice is a valid set combo.
I'm a returning player so all my CoX-fu has dissipated and so I need help hehe
Thanks in advance!!