I love the VS08 Javascript IntelliSense; it's fast, useful and informative in combination with VSDoc.
The only bug I stumble up every time I code, is the IntelliSense within a private closure. I'll give an example of what I mean:

(function($) {  // private closure;
	$(function() {
		// do stuff;
	});
})(jQuery);

The problem with above code is that the argument $ in the function isn't given the data from the variable jQuery. So the advantage of IntelliSense within the closure is totally lost.

But yesterday I come up with a solution for all server-side scriptwriters (in this case ASP.net) that works in 2 ways; usefulness and source.
The solution is useful in the way that it should add IntelliSense for the arguments with the least amount of code.
The other way is that it I don't want the solution to be seen in the page source. I like my source clean and informative.

So here's the solution:

(function($) {  // private closure;  <% /*debug*/ if (false) { %> 
	$ = jQuery;
	// <% } /*end debug*/ %>
	$(function() {
		// do stuff
	});
})(jQuery);

The part that adds the IntelliSense is the $ = jQuery;. But the important part is the if (false) {. This causes the code to work while developing, but not to print it on the source.

After fixing these problems another problem raises. You can't add server-side inside Javascript, causes an error, which then stops the IntelliSense again. The solution for this problem was to put the server-side code in a Javascript comment. That easy and the server-side code still executes.

I hope other find this useful too, gr J