50mm is always a nice lens to carry around, I dont do it often but the size/weight is crazy, not to mention the superb quality
I would leave the 17-40 at home and perhaps take the 100mm if you are really going to need that kind of shoots (nice bokeh portraits or even macro)
the 24-70 is a must, its
my lens, since I got it (2011 summer) I haven't used other, not that I have much more apart from it, just the nifty and the "old" 18-135