I am bit torn on this subject. I have a mix of primes and zooms. I prefer shooting with the primes when I have an opportunity to be a little more deliberate. I feel they really lend themselves to more creative options. I do most of my portraiture work with primes.
But events are another matter. I just shot a wedding this weekend using the new Tamron 24-70mm VC over the focal range where I would normally use a 35mm and 85mm prime. I found it a much better tool for adjusting on the spot and enable me to better frame key moments without worrying about not having enough room in my framing. I shot it about 65-70% of the day, complimenting it with a 135L, 100L Macro, and 85mm f/1.8 for key shots where I could be more deliberate. I was really pleased with my results, and, from what I understand, the MKII of the Canon 24-70mm is even better (although that VC is very, very nice!)
The same is true to a much lesser extent of a longer lens (like a 70-200). I find longer shots easier, because you can always crop a quality image to get closer, but you can't add width to a shot in post. I love both my 100L and 135L for event work for different reason. I also add a 1.4x teleconverter to the 135L to make a 189mm f/2.8L (which is about as long in actuality as the 70-200mm zooms) on occasion.
I love having both options, but I think choosing one depends very strongly on one's shooting style.