Ars Technica has a review of iWork'09. iWork is, as the name might hint, an office suite for Mac OS X.
I bought it together with my two new Macs, so I've had a chance to try it out myself.
I have been using iWork'08 for about a year, since I got my first Mac (at the office) and I am very pleased with Keynote and Numbers (although the latter is not something I use a whole lot, but on the few occasions where I need a spreadsheet I find it quite nice). Pages is ok, I guess, for shorter documents, but for any serious paper writing I use LaTeX anyway, so I haven't used it that much.
Compared to '08, there isn't a whole lot new in '09. A few more templates, a "share" menu item instead of "export" (where "share" also allows you to directly email documents in various formats) and a "full screen" mode.
None of the features would be enough for me to upgrade by itself, but since I bought an iMac for home and a MacBook for travelling, I needed to get it for those anyway, so I got a multi-machine licence and installed it at the office as well.
If you have a Mac, I recommend it just for Keynote. It is by far the best presentation tool I have used. Pages and Numbers is just a nice added bonus.