For anyone involved in web projects it's interesting to follow the development of services that are really raising the bar of what has been done before. I believe there are two interesting areas to follow right now; Web Office and Application Creation.
As a coincidence two different blogs today have put together overview of those.
Those are the ones aiming to (in the long run) compete with Microsoft Office, for example Googles Docs & Spreadsheet and ZoHo. The Read and Write blog has a great overview in this post.