I started out as a fire mage and leveled as fire till 50-55, I dont remember anymore what level I switched. I liked fire, but I did die alot. I then started to look at the arcane talents and was looking at how it gave alittle more survival than fire, but the damage was still decent so I tried it out and loved it. Took arcane till 70. At 70 I tried out frost and absolutely hated it and when back to arcane. I leveled arcane from 70-80. its damage was decent. I raided with arcane then tried out FFB spec for raiding and it did better damage, after the arcane update went back to arcane and I love being one of the best dps classes out there. I have done alot of research on most of the specs..but it kinda comes down to what spec ya like and what you can live with.
Fire = Decent/great damage depending on spell rotation, Enough AE choices that you can take on a few extra mobs. High DOT effects. a straight fireball spec I hear is also great dps. Fire is easier to manage mana use.
Ice = lower damage than fire/arcane but this depends on player skill and rotation..I have seen ice mages almost keep up with me. Alot of survivability. Can take on large amounts of mobs. Multiple Ice blocks / frost novas and an elemental that helps CC, deal damage, tank, AE
Arcane = Shines more at higher levels, also good for pvp cause of ability to cast instant spells deal high burst damage. Decent/great damage depending on rotation. Offers some survivability/ not like frost. One of best single target dps specs. doesnt offer alot of AE choices, Arcane Explosion is fun but expensive . This spec also offers high burst damage, but it can burn though mana in minutes.
I hope some of this helps