I bought iWork '08 today and I'm getting to know Numbers. So far, so good. It's really clean and slick, and the editable "print view" is quite cool.

I've used AppleWorks to do spreadsheet stuff for about 5 years (coincidentally that's probably when they released the last version), so anything new is a big improvement. I also own Excel, but it's so heavy, bloated and slow that I'd rather use AppleWorks instead.

Anyway, Numbers is great. Big props to the iWork team for re-thinking spreadsheets. One cool feature set is "checkboxes and sliders". They let you treat cells as "on" or "off" (checkbox), or allow you to modify the value across a range (slider). Both are simple to set up and use, and right away make your spreadsheet much more dynamic.

Here's a video tutorial showing checkboxes and sliders, and another one showing the editable print view.