This book sounds like it will be really practical and useful! The author tackles issues he’s faced using jQuery with ASP.net controls, and highlights useful combinations of the two. You can pre-order the ebook today for $10!
51 Tips, Tricks and Recipes with jQuery and ASP.NET Controls
Dev42 - Scottie's Developer Blog 
Asp.net control is more flexible for your webpages and create more interactive website.
Thanks for your feedback! Sometimes you just want to do some light-weight client-side scripting to accomplish a few things, and that’s where the jQuery comes in real handy. You don’t have to pick between the two though–and in fact that book I linked is about using the two together (ASP.net controls augmented with jQuery).