Personally, I hate Microsoft Office on the Mac (it's ace on Windows) they've just tried to make it too pretty and fancy... and failed. With that said, I've not used any other office suite on my Mac (I've no use as I don't currently have a need to create those types of document).
The only other one I know of which you haven't mentioned would be OpenOffice, available to run on OS X under the X11 windowing system, of which there is a native port called NeoOffice (http://www.neooffice.org/).
So other than my dislike for MSOffice (on the mac) I can't really offer an opinion on the best.
I've got iWork and I like it. Pages is great considering that it's only the first version. The interface is good and the templates are very nice and extremely easy to use. It has some improvement ahead, but it's good for version one like I said. I've not used Keynote much, so I can't really comment on it. $79 is definitely a deal.
I also like NeoOffice. I work Helpdesk and we often use OpenOffice on Windows XP to clean up MS Word documents that become corrupt due to converting from Word to WordPerfect and back to Word as well as individuals just copying and pasting text from the internet into Word documents. You can get OpenOffice for a Mac, but you also have to make sure X11 is installed on the Mac. There are also a few other tweaks to get it going right. NeoOffice is an Aqua version of OpenOffice native to OSX. The only draw back for me so far is that I have to launch NeoOffice and it opens in the Writer. I then have to do a File, new - to specify a Spreadsheet or Presentation or Database.
If you are interested in Open Source code you should first visit SourceForge at http://sourceforge.net/ Then take a look at Open Office at http://www.openoffice.org/ and finally check out NeoOffice at http://neooffice.org/
Ep, glad to see you come back and tidy up...did want to ask a one day favor, I want to enhance my resume , was hoping you could make me administrator for a day, if so, take me right off since I won't be here to do anything, and don't know the slightest about the board, but it would be nice putting "served administrator osnn", if can do, THANKS