Read about some "Ready-Built ASP.NET Components" (the English on that somehow doesn't sound right though) while checking out the MSDN mag CHM (mentioned by Stephen Toub here) and decided to see what they offer.

What really caught my eye was the name of the company "Can't Be Done Software" which manufactures this set of ASP.Net components and functions (called ASPXPand) which automatically creates the client-side scripts and DHTML etc. for you. I think it's great to be able to use a message box on a web app just like in a winform app, so am really tempted to try these guys out when I start working on my web site. They offer a free download of a component, WebEffects, which can be used to spice up a site as well. I like the Cross-Hair Cursor and would like to use it in an online game if I ever get down to it.

A couple of things which I have faced and needed first-hand are the ability to display a message box to the user and being able to disable or remove a button the moment it is clicked (as when clicking on a Submit button). Both are possible using client side code, but it is so much easier to focus on the app if this complexity is hidden away and available for use as part of the server side code you are writing.

Any one know of any other such components worth checking out?

Only catch with ASPXPand is that it only supports IE as of now. I tried the demo on Netscape and was pleased to know that most of the things in the demo at least worked in some way or form even on that browser.