My 2 cents worth:  I have spent almost 800g respeccing and trying diff builds, for pvp, pve, arena, Gruuls, Kara, Za, SSC, Mag, and I keep coming back to affliction.  Playing affliction is very easy on your healers in your raid group, you will 99% of the time not pull aggro, i use a demo/affli build i am not worried about my bonus spell damage as much even though i do have 1200+  What I focus on is stamina and intel, I have 13k+ health and 11k mana and i can dot the heck outta four or 5 things and watch them slowly die.

But play how you want to they are all a blast..