bubblenut wrote:.....Another one woth a look in (although I've done no more than a quick play with it) is Dojo.
I've actually been working with DOJO, helping bug find, and offering ideas for the past few months... I've also checked out a few of the above, and one thing that I've liked about DOJO... quick responses to bugs, if they are missing a feature that could benefit the project, they often add it the day after you request it, they name space everything so you can combine their toolkit with just about any other w/o collisions. And they are almost all professional javascript/dhtml programmers that do this stuff for a living as well. They are definately doing big things with javascript these days. I'd recommend you checking it out as well.
There is also MochiKit which wasnt mentioned, another toolkit, and the creator of it has given DOJO permission to use anything from his toolkit, so I'm expecting they will eventually merge... but that remains to be seen.