Ajax 13, a very young startup from San Diego, has developed an impressive collection of very, very sweet AJAX Office applications:
There are a write app as well as a spreadsheet tool which, if they want it to be successful, will surely have to try hard competing with Google's recently "hyped" Docs & Spreadsheets.
However in addition to that they also have a presentation tool (ajaxPresents) that -- judging from my first impression -- looks and feels pretty much like the big standalone applications, Powerpoint and OpenOffice. It can also export and import these two file formats, which makes it a brilliant tool to edit presentation slides on a computer where you happen not to have an office suite installed.
But there are even two more on the list: A drawing tool called ajaxSketch (conveniently exportable to SVG) and an online MP3 player called ajaxTunes (if I see it right, it's Flash, not AJAX, but ah well).
All in all this seems to be a very interesting company to keep an eye on; and I would not be surprised if they made it on the list of Google acquisitions some time soon -- just like Upstartle, the company which produced the tool Writely, now part of the aforementioned Google Docs & Spreadsheets.