Office.... one of my least favorite apps for the PC. My change to mac has not helped me here. Office 2004 for mac is a pig. My opinion could be skewed because there is no universal binary and it appears Microsoft might not be releasing one. Let me tell you, running word/excel/entorage on an intel mac is HORRIBLE! So i went looking... and i found a couple replacements.
Open Office will run on a mac no problem, its butt ugly and you have to load x11. For me open office works fine. I am not a heavy office user. I work with some spreadsheets and a few word docs here and there. Nothing crazy and I'm not in the application all day so for me open office appears to have all the functionality of MS Office. I would have stopped here, but for most people i think the loading x11 step will stump most users. So I looked a little more.
ThinkFree Office comes in two versions. A free web based version and 49.99 desktop version. I have tried both. The web version works with safari, but I ran into some problems with it. I couldn't put pictures into my documents, changing fonts, size, color was troublesome at times. I had none of these problems when i would run it in firefox for mac. The web version also comes with 1gig of free online storage. There are a ton of additional features such as posting documents right to your blog, exporting in many formats and other misc perks. Being that i use a laptop I couldn't just settle for an online only version of the application so I loaded up the desktop version. It is very similar to the web version but allows some things the web version wont. Like when I can double click .doc files and it will open with ThinkFree Office. The web version cannot do this. I think for $50 it is a great deal. This was my personal favorite.
There are a bunch of web 2.0 office replacements, but if I dont have internet access I still need to get work done. I might write a review on the web only office suites... but for now i cant rely on them so I wont bother. Long story short, try ThinkFree Office 3.0 you can download a free trial and it runs native on intel MACs.