I've found that when traveling I've far, far more often regretting taking along gear than I've regretting leaving gear behind.
My aha moment was in Yosemite when the brilliant 43mm lens got stuck on my Mamiya 7, and that was all I could carry while trecking up and down. My frustration with the camera turned into relief. I love the photos I took and can't remember any that I couldn't take.
I think part of the reason we, at least I, obsess about taking "enough" gear is to justify their cost. Why in the world did I spend so much on that glass if I'm not taking it on a great photo trip?
I just came back from a trip to a very scenic part of California with just the 907x 50c and 45p and my trusty little Sigma DP2-M. I ended up mostly leaving the Blad in the hotel. and love the Foveon photos.