OneWorld,
Do you need Outlook? Every Mac comes with "Mail", Apple's own email application which will even import your old Outlook mailboxes. It will connect to POP, IMAP and Exchange mail servers.
Regarding NeoOffice and iWork compatibility with MS Word, the results should be the same when opened on a Windows machine. When using Apple's "Keynote" for presentations and exporting them as PowerPoint, there are sometimes issues regarding some formatting and effects. Essentially, the effects in Keynote are much better than in PowerPoint and it can't match them in the export. Some amount of editing can be required on the (PC) PowerPoint. It depends how the original Keynote presentation was designed.