With the advent of synergies, you could go much more powerful just sticking with one tree. But that makes Hell all the more difficult. But if it's for fun then have fun, I'm currently working on a Lightning Sorc myself.

One day when I finally leave work I will get on (yes it's 8:15 and I've been at work for 10 hours, someone please make this gel finish running so I can go home, please).