As you may or may not know, Google recently unveiled it's newest beta: Google Spreadsheets. It's more or less a stripped down version of Excel, and it dosen't seem half bad.
What's really neat though, is I can now do everything though Google that I'd do though Microsoft Office. Note that "Google Office" does not and never will have as many features as the Microsoft stuff, but it has almost everything your Average Joe would need.
All we need now is an online database app and a presentation tool. Then we can watch Google roll it all up into one coherent service. Remember back when your Yahoo ID could do like half a million things and it was the wave of the future? The concept has returned, on a whole new level.