Welcome aboard PalmBeachEd! Yeah I think Adobe PDF is pretty much the Portable Document standard. It retains the original format whatever you export it from and the reader is accessible to nearly everyone. Software required is Adobe Acrobat Standard or better (Professional, Enterprise.)
Basically you install it and can export PDF from whatever program you are comfortable in. Although some programs can export PDF's without having Acrobat installed, from within Acrobat you can create a hyperlinked table of contents and all sorts of other things important to a publisher.
If you're going to create an e-book, you will want all the indexing and hyperlinking features in Acrobat that are not available with the online version. It will also be faster, no uploading/downloading.