It's screen captures like this that make Windows look terrible compared with OS X:

It seems odd that Visual Studio doesn't get "files from the Web..." on a separate background thread. I realise there's not much else I can do with the app while this is happening and so as a developer multi-threading doesn't immediately spring to mind, but by performing a potentially huge download on the main process thread I lose control of the app completely. What if I wanted to cancel?

By version 1.0 in CSSVista I'm going to have at least tried it out as a completely multi-threaded application. That is, every operation that may cause a delay, regardless of whether the user should be able to use the app during this process or not, will be on a separate thread, feeding back to the main thread when appropriate - maybe even a separate process if appropriate.

Even if the main thread is showing a modal dialog with nothing more than a loading indicator - this is better than 2 UI's merged together in a big, unresponsive mess.

Somewhere between Windows 3.1 and XP it seems to have become acceptable for larger applications to swing in and out of a "Not Responding" state without worry - "Oh, it just does that while it's loading - I'm opening a very big project after all".