Superman, himself's, powers are currently unknown. He actually mostly uses Iconic Powers as well. Fire is a tank-based power set which sorta fits into Superman's fighting style of just tanking whatever (notice he never blocks unless he has to). It also fits into Superman's deriving his powers from the sun.
If you didn't know, City of Heroes and Champions Online, provide a Superman like power for defense; Invulnerability/Willpower. I was surprised myself to only see Ice and Fire as defense sets. Especially when two out of the three Hero Mentors use Invul and or Will. Ice Tanking looks cool (no pun intended) but we need more tanking sets.
"Heaven cannot brook two suns, nor earth two masters."
Ice has powers that reduce damage (and one that negates all and heals you for a short time) as well as some nice damaging powers. (I use Frost Blast which has a short cast time but OHKOs entire mobs easily). I quite love Ice. I'm playing fire now too but I'm not liking it quite so much.
Well man and god both come from technology and technology comes from man and God and god comes from man which comes from God which might come from man, see?