when I export to Powerpoint and then try to run the presentation on my Windows XP (work) PC, the presentation is misconfigured with fonts running off the screen and picures misaligned. Animations also seem inconsistent.
Why in the wide, wide wonderful world would you want to prepare a presentation with the particular appearance you want in a particular application and then proceed to complain that you cannot have that particular appearance in another application?
If what you want is to preserve appearance, then use an application-independent portable page description model. There is one built into Mac OS X. It's called the Adobe Portable Document Format and while it has its problems, preserving appearance is not one of those problems.
The whole idea these days is NOT to have to buy Microsoft Office in order to interchange digital documents. Instead of everyone buying Microsoft Office, everyone selects an intermediate and application-independent format for interchange. ISO has published two such sets, one set for content interchange (ODF and OOXML) and one set for appearance interchange (PDF). ECMA is working on a second appearance interchange format (XPS).
Acrobat in the free Windows version will image your PDF presentation.
/hh