Don't waste your dollars on commercial office suites
If you haven't tried Open Office and Neo Office for the Mac lately, ... well, you should. As some open source projects do, OO has very active communities and developers (paid by Sun, no less). You might be surprised are how much it has evolved since the time you tried it last. Neo Office is an OO's Cocoa/Aqua port, so you might want to check that out too.
If you don't have time to test the free software, Mr Christopher Dawson has a decent review of the four contenders: OO, N-O, iWork and MS Office. Link
However, if you are still writing your thesis in a commercial word processor, may I suggest you switch to LaTeX already?