There's a beta version of this popular and free Office package now released for public testing. By this point most bugs have been sorted and it ought to function smoothly. From a quick glimpse this is a genuinely new version and offers a smart interface and plenty of features. Of course, two reasons alone make it worthwhile for many (other than being free!).
You can save as or open pdfs which Office 2007 will not. You can open Word2007 documents which WordXP will not (without a shove and a push from a converter you need to download).
Give OpenOffice 3 a try - and do feed back any things you'd like changed to the OpenOffice developers. Links to how to do that are available at the software download site.