jQuery is not just good, jQuery is great! At Clarisoft Technologies we used it because it saves lot of time, resulted code is much simpler, and there are many free components out there.

You can see how we used jQuery in our own web site:
1) scrolling images at the bottom of the home page and image gallery
2) really nice filtering in our portfolio
3) rotating images on the top left of the home page.

Below are links to some of other jQuery components:

40 Exceptional jQuery Interface Techniques and Tutorials

20 Excellent JavaScript Navigation Techniques and Examples

Though there are some issues if you try to integrate with AJAX pages built with Microsoft.Net, lately Microsoft is showing better support for jQuery. So, you can start using it too!