Honestly Arcane missiles is my favorite spell in the game. But oddly I can't get into arcane as a spec. I love frost and PvP (even though i'm average at best at it). Improved blink is awesome for pvp and questing/leveling in general. I became much better at PvP after I got it.

@Mr. Mage Pants: Bravo. That is all.

Improved Blink is wonderful, let me tell you.
I've been an arcane mage forever. I've dabbled in frost and fire here and there for whatever reason, but I just feel comfortable arcane. And don't let anyone tell you that you should only PvP as a frosty. Sure, it's a lot easier to survive, but I can't seem to get the killing part down. Improved blink, Incanter's absorption's knock-back, instant-invis, SLOW and having PoM around to make whatever you need an instant cast are all terribly useful. Just remember that the best defense isn't an Ice Barrier, it's not getting hit at all. It's been proving difficult to get to work consistently well in Arenas, but for any of the BGs I top the charts with honor and HKs.