Actually, using the Browser as UI can make developing the UI easy -- if you're already used to doing it. If you are -not- worried about cross-platform issues, then its -- to me -- ideal.

IE is installed on all windows systems ... it has to be for the Windows Explorer.

IE lets you create things called .hta (hyper-text applications). You can call DLLs and other operating system bits from your hta's. You can embed perl (perlscript, via activestate). You can easily ditch *all* the browsers native chrome and just use an empty window as a starting place. You can create components with defined behaviors (via .htc files) that are easy to reuse.

No, I'm not a big MS fan, but I have used IE as interface for desktop based, custom, windows apps. Hit MSDN and start reading about IE ... you'd be amazed at how much they've done to make this easy and powerful for you. I think few poeple take advantage of it because .. its 1 platform and its microsoft. I don't blame 'em.

- Erik