Hi Patrick,

You have an interesting kit. At first glance I was thinking you were missing a general purpose zoom. But in looking at it for a bit longer I can see how your kit would work well as you have 17-40 and 70-200 are covered at f/4, filling in the 50 mm gap with the 50 f/1.4.

If you find yourself always changing lenses, I would be tempted by a general purpose zoom like the 24-70 II (or 24-105 f/4). Given that you have a two year old and shoot events like weddings, I can see wanting faster glass to get a more shallow DoF. If you shoot the general purpose range more that could be accomplished by the 24-70 II or with primes at 35 mm and 85 mm. If you shoot the telephoto range more, then I think it is hard to argue with the 70-200 f/2.8. However, I have been looking at this, as this may be my next lens purchase, and comparing the f/4 IS to the f/2.8 II. Looking at sharpness results, they are very similar with a slight nod to the f/2.8. Regarding the DoF, playing with the calculator @ 20 ft they have the following minimum total DoF (f/2.8 total DoF-f/4 total DoF): at 70 mm (2.7/3.8 ft), 100 mm (1.3 ft-1.8 ft), 135 mm (0.7 ft-1 ft), and 200 mm (0.3 ft-0.45 ft). To me, both should provide a shallow DoF if stopped down. I am sure those that own the f/2.8 can let us know if the the quality of blur is better (I am planning on asking this before I buy, which won't be for awhile). However, just playing with reviews on this website, it seems to me that the bigger benefit of the f/2.8 is vignetting. Even at f/2.8, the f/2.8 has better vignetting than the f/4. Ok, I digress a little.

All of that said, I agree with the others, as long as you are typically shooting in the general purpose range, that is where I would upgrade. I initially balked at the cost of the 24-70 II, but after hearing/reading such good things about it and adding up the cost of 2-3 primes to cover the same range, it seems worth the cost.

Good luck,
Brant