@Rubbish: I'm curious why you compare this to CoffeeScript. I love CoffeeScript but I don't really see any comparisons. TypeScript gives you modules and classes, maybe that's it. I think that TypeScript gives you more than that, especially if you're using the VS tooling that comes with it. I use a Mac and roll my code in SublimeText 2, so tooling support is as of yet non-existant, but using something like Guard and LiveReload it should be pretty straight forward to get some large application work done with TypeScript that might even surpass what I've done with CoffeeScript by way of productivity and maintainability. I'm thinking especially how CoffeeScript gets muddled when spread across a large number of files or, heaven forbid, we have a massive single file of CoffeeScript. How often have you run into an issue related to incorrect indentation level or methods that look like they just run together? I think TypeScript will help with this.
@Vineel Kumar Reddy Kovvuri: From what I've seen, there are these declare files (plain old JS files) that provide type hints for common libraries that light up the awesome tooling. I believe there's already a declare file for jQuery. Also, if there's a declare file not available, it's pretty straight forward to role your own.