Originally Posted by
Trowski
I don't know what lenses you have already, but with the 5DII and 24-105mm f/4L I'd recommend the 70-200mm f/2.8L IS II if you could afford it ($400 off is a spectacular deal!), otherwise the 70-200mm f/4L IS is very similar in image quality, mostly you're just losing a stop of aperture. The 16-35mm f/2.8L would fill in your ultra-wide angle well, and it's a great lens. If you're into macro, I love the 100mm f/2.8L IS macro lens.
You might also want to consider an external flash if you don't have one, since the 5DII doesn't have a flash at all.