I recently read Ed Kohler’s comment where he has ranked the importance of various "Google Apps" programs in the following order:

1. Docs
2. Presentation
3. Spreadsheet

However, I beg to differ.

In my personal experience I have found spreadsheet to be most used online collaborative tool of the entire office suite.

An online spreadsheet can be used in hundreds of ways for different purpose and help you collaborate much better for several reasons:

1. Spreadsheets keep data in a more organized way which can be further imported / exported as a comma delimited file and also imported / exported from a third party database

2. Some common usage can be sales tracking, basic level project tracking, bug management, issue tracking, any collaborative data gathering, managing petty accounts, etc. The list is endless. You cannot do all this using word processor or presentation tools online.

3. Every spreadsheet has several sheets, which enables various versions of inputs to be gathered from different sources, all put together in one place with a very easy-to-shuffle mechanism.

May be my opinion is based on the way I use Google Apps!
What is your opinion?

Abhishek