Interesting talk from Dan Gilbert on the factors driving satisfaction and (Dan concludes) happiness in humans. This one is worth listening to help understand your own reactions to choices, as well as to help you decide how to present choices and options to users of your products, people you are negotiating with, and so forth.
Go listen to it first, but if you want the summary here's the short version:
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Humans are able to "synthesize" happiness when there is no choice, but become deeply dissatisfied when offered too many choices.
Actually that's quite a poor summary of his point; go listen to the talk.
This was similar to but significantly better than Barry Schwartz's talk.
Btw, the vast majority of the Ted Talks are worth listening to.