I can recommend Prototype as well.

Also, there's this great talk by a person who KNOWS about JS:
http://www.youtube.com/watch?v=hQVTIJBZook
(I know it's an hour long, but I really took some lessons out of it. I think
it's worth the time investment)

and his great tool:
http://www.jslint.com
that helped me remove a lot of errors from my javascript stuff...


In the german JS-newsgroup the one and only answer to the question 'which
> JS-framework should I use?' is 'write your own. The existing ones are all
> bullshit'...
>

I like that one ;-)

There are tons of frameworks out there, just pick one that has the kind of
syntactic sugar you favor...
Greetz!