This time it's more than a tip. I've one recommendation. As we have seen, the SC jQuery plugin enables us to detect whether the jQuery library has been loaded or not.
Though it may be a lot of work, I really think that in a real-world site, it would be useful to modify the plugins or modules we use to detect if jQuery has already been loaded, and then choose to load it or not in each case.
This way we can remove some conflicts between extensions and also save a huge load of bandwidth.
The problems are that if we install a newer version of those plugins or modules, our changes will be lost. But in any case, I think it's something to consider.
Also, by modifying the SC plugin to work as the Google Ajax, one can end up with less bandwidth ...