I've blatantly robbed this slide show from John Resig, the founder of jQuery:
I like John's approach of effectively saying "all the other libraries are great, but jQuery is the best". He takes a far more subtle approach than I do - I tend to just denounce the other libraries in the bluntest manner possible (no time for tip-toeing around) whereas John nibbles away at them showing that overall jQuery really is in the lead.
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Great overview - it seems jquery is a good choice
Peter