There are a few ways you can go with specs for Sorcs, Healing is obviously Corruption, Lightning is better for PVE (for me anyway), Madness is more of a PVP spec.
My main is a sort of hybrid between Madness and Lightning and it's been working very well for me. Basically I focus on Madness at first just to get Death Field and Madness (Madness makes it so there is no cooldown for Force Lightning which is probably the reason you see people spamming it). Then I focus only on Lightning afterwards.
Instead of talking about it I'll just post a link to my skill tree. http://www.torhead.com/skill-calc#201ZfobMdRrupZcMcRo.2 The only awkward thing about it is that you can only put 29 stats in Lightning.
Hope this helps or gives you an idea for a different skill tree. Also note this tree requires you to use a lot of AOE attacks, Death field and Force storm are very good with this tree. In a fight start off Chain Lightning, Then Death Field, then Force Storm.