I’m anxious to see Google’s spreadsheet product, because I strongly suspect that it will do 99% of the things that I actually use Excel for, which represents about 2% of its overall capabilities.
Excel is an interesting product to me, in that it’s as close as you can get to being an application development platform without actually being one. I’ve known plenty of people whose job consisted mostly of writing Excel macros. I don’t think anybody’s Web application is going to take the place of that.
For me, though, Excel usage consists mostly of entering numbers and letting Excel add them up, or average them, or otherwise manipulate them. Even more unfortunately, I often see it used as a way to ship around tabular data, which I usually have to export as CSV so that I can get at it programmatically. There’s no reason why a Web-based product couldn’t take that over either of those functions almost completely. The main barrier is in presenting an interface that’s anywhere near as usable as Excel’s.
As a developer, I’m very curious to see how Google tackles that problem.
(Here’s a link to a tour of the spreadsheet application.)