Read/Write Web has a round up of online office suites. 
Mashable and Valleywag have articles on Google's buy-out of Zenter, an online PowerPoint.
I cannot see the point, to be honest. The best thing about the Web is that it's made all these office and productivity suites irrelevant. XHTML and XML have just supplanted all my document needs. More often than not, I'm needing to move data around and manipulate it. I'm finding that, more often than not, storing it as some kind of XML document and then using XSLT to transform it to a Formatting Object or XHTML+CSS file does the job.
As for spreadsheets - what is the point? What can I achieve by using a spreadsheet that I can't achieve by writing a Python script, for crying out loud, except that I'm limited to data being in two dimensions ratehr than as many dimensions as a multi-dimensional array (sorry, dictionary/tuple combination) can be in.
Presentations are handled excellently by S5.
I'm not sure what the point of porting outmoded 'office/productivity' paradigms to the web are - productivity software makes me a lot less productive because it's designed for some mythical average user. If I have an XML document or a Python script, I can run it however I want. All I want is a really great web-based ASCII and XML editor which supports things like XSLT natively. How about it?
The future of web applications is simple - stop making generic tools and start makign specific tools that aggregate togeter. For instance, if you are creating a business form, don't bother with a word processor - have a specific component that is designed for making forms well - perhaps a decent, web-based XForms editor.
Beyond testing, I have never used Google Docs or any of it's equivalents for anything. It's utterly pointless. Whatever machine I'm on has a text editor. I've got a brain. I can format my own goddamn documents.
