Thats good - Ive bookmarked this so when I get my MacBook I wil be able to come back!
Alright, just so you clear up a little of the quick advice you've gotten here...I'll go through your options again:
MS Office for Mac 2008 ~ This is the Mac version of MS Office '08, with a few differences. You still have the exact same Word, Powerpoint, and Excel (pretty much), and instead of Access and in place of Outlook, you get Entourage, which is an Email+Calendar+Addressbook suite. Missing from MS Office '08 is macros, although it now supports AppleScript. Get it if you need full compatibility with MS Office for business/work/etc., i.e. really complicated Excel spreadsheets and so on. Personally, I think that's the only reason you should get it, as it's the most expensive option.
iWork '08 ~ This is Apple's office suite for Mac. It's much more "Mac" than MS Office for Mac. Many find it to be more intuitive and generally a better experience to use than MS Office for Mac, but somewhat less powerful as far as Pages (like Word) and Numbers (like Excel) go, if you need the really high-end Office features. Most agree that Keynote (like PowerPoint) is an excellent program, however, and many find it superior to PowerPoint. iWork is significantly less expensive than MS Office, and--while it can't save natively to office formats--you can "export to .doc," "export to .ppt," so it's somewhat compatible if you need to send to a PC. If nothing else, saving to .rtf always works for everyone. Get this if you want a very "Mac" program that's very high quality, but not quite as compatible with PC's (although you can still send files to them, easily).
NeoOffice ~ This is what I use. It's the native OS X port of the popular free, open-source office suite OpenOffice.org. It, too, has its own versions of Word, PowerPoint, and Excel, and has all the features most users will ever need. Obviously, it won't suffice for high-end users of Office who need full compatibility for corporate purposes, but it should be much more than sufficient for the average user. I've never found anything lacking in it. Since it's open-source, programmers all across the globe read the source code and make sure it's relatively bug-free. It has full compatibility with MS Office (ability to save natively in .doc and even the new .docx formats, etc.) and even offered support for the new xml formats before Office 2003/4 could open them. Best of all, it's free. Get this if you want to save money, don't need the full compatibility of office, and aren't bothered by the lack of certain higher-end features.
Last word ~ You can try out all of them easily. 30-day trials of both MS Office for Mac and iWork are on your computer, so just see what you prefer about each. NeoOffice is a free download, so you won't be losing out on anything by downloading it just to try it out. Try them all; see what works best for you; I personally recommend NeoOffice, since it's free and I've never had a problem with it.
