Hi everyone, I am new to this forum. I need help deciding on camera lens.

I am a casual photographer. I shoot a lots of live concert pictures. I own Canon 30D camera and looking for new lens. I've heard so many good things about Canon EF 70-200mm f/2.8L IS USM lens and my mind was set on this lens. Now that the new Canon EF 70-200mm f/4 L IS USM is out. I'm torn on which to get.

Any help is greatly appreciated.

Thanks in advance.