2 - 5 seconds is massive in terms of page load times, and I definately wouldn't want people waiting for the jquery libraries to load unless I was using them extensively throughout my site.

There's a lot to be said for hand-coding features in Javascript. If we all rely on using jquery for every little effect we want, then who's going to be around still with the javascript skills needed for creating better alternatives to jquery in the future? I'd like to think that people who use jquery can still write their own javascript and understand why jquery works (or doesn't), and how to customise jquery for their own purposes.