We are going to New York City for a family vacation this summer. I would like to pack very light, but I don't want to be constantly saying to myself, "If I only had ...(insert lens here)... with me." I'm sure we will be doing a little bit of everything the city has to offer.
I'll be shooting with a 40D. My 17-55 is an obvious choice. Am I going to be hating life if that is the only lens I take? My gear list is small, but I am open to suggestions. I'll probably take the 580II too since it is somewhat small (no clue when I'll use it, but you never know - luck is that it'll probably stay in the room though).
The wife and kids will be using the Canon SD1100IS P&S.
Anything that is "can't miss" with middle aged kids?

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