I've not had any problems with slow start up due to Mac Office. From what I have heard, Leopard OS has a slow start up in general (though still faster than Vista ), but rumor has it that they are coming out with an update in the near future to fix that.

While I don't like Microsoft, it serves its purpose. If your processor speed and RAM are good, you'll be okay with it. There is an alternative to Microsoft called Open Office (http://www.openoffice.org/). It's basically Office with slight variations... and free. I've used it in the past and it's worked fine.

With the new processors, you can run Windows on a section of the Mac, but I haven't found a need to do that because the programs I have are made for Mac.

Good luck with whatever you decide to do.