Getting back to the original poster:
There isn't much difference between lenses at smaller apertures; most lenses perform pretty well at f/16, but at wider apertures (f/4 and below) the expensive stuff will really distinguish itself from the coke bottles. Faster glass is more expensive, but allows you to shoot in lower lighting conditions successfully, and will autofocus more accurately. If you shoot indoors much, I'd recommend saving extra nickels and working out and buying f/2.8 instead of f/4.
The 24-70/2.8 is a very good lens; mild CA at the wide end (easily corrected in ACR) with a bit of barrel distortion, but again this is easily fixed in PS. I have the 70-200/2.8L IS, and while heavy and expensive, it is sharp at all apertures and zoom settings with only the barest hint of CA and other imperfections (again, easily removed if you can even find them). The f/4 version is also very good quality; the main things you're giving up is the extra stop, some weight, and pain of acquisition. I recommend getting IS if possible; it makes a big difference when shooting handheld in low light, and also when shooting from a tripod in windy conditions.
The 17-40/4 L, 24-70/2.8L, and 70-200/2.8 L (IS and non-IS) all have the same 77mm filter, so that cuts down on the number of polarizers and other filters you need.