Keynote is perhaps the star of the suite though allowing you to create very impressive presentations with less fuss than in Powerpoint. Numbers allows you to write formulas for spreadsheets that many users may find easier than the dreaded Excel. Pages allows you to create professional looking brochures, flyers, reports and resumes quickly and easily.
The three main components of iWork are Pages, Numbers and Keynote. If you've used iWork '08, then you won't notice much difference in iWork '09 but it still retains the elegance and usability that make it a worthy competitor to MS Office. Also you'll need at least 20 minutes for it to install.
The first thing to note is that iWork is quite a big package so you'll need at least 1.2GB of disk space free to ensure it works properly.
