I recently purchased a 5d mark II with a 70-200 f2.8 IS II lense. It was an upgrade from my 40d wi kit lense. I'm looking at an external flash for my next purchase. I'm not sure if I should go with the 430EXII or the 580EXII or anothe option altogether. I'm not a professional photographer. This is just a hobby for me, but I'm getting more into it and want to improve the quality of my images. I'm looking for a flash to improve my indoor photos in low light situations. So what do you guys think?