Even the most ardent of declarative programming hacks will appreciate the way toolkits such as jQuery allow painting of behaviour onto pages rather than littering semantic markup with snippets of script.
As is my habit in programming languages, I've found myself move from framework to framework depending on the actual tools available. Starting off in Prototype as it came with Rails, paying a happy visit to jQuery because of Thickbox, considering Dojo because of its rich text editor, and now being wowed by Plotkit and thus checking out Mochikit.
So, here's an idea for aspiring XTech presenters: we'd love to hear more about these toolkits. Experiences, future plans for the kits themselves, and how developers should choose between them.