Egh, you know how OS X works. Unless space is at a premium, there is really nothing about installing a program like NeoOffice on your computer that ramshackles anything.
Anyway, I do have to say that Keynote seems like a gorgeous program. I have no desire for Pages, and honestly, Powerpoint works well for me. But Keynote does produce better presentations than Powerpoint. Buying it purely for the purpose of viewing other people's presentations seems like a waste of money to me, but....
...I'll stop the argument now.