You must get this all the time. There are lots of us who don't sync to a desktop very frequently, we just fetch our email and use the attachments. Docs2go uses native format files as well as its own internal versions.
People like me need the Palm reader to handle the pdf directly, so we can keep documents on SD cards and use email attachments to pass them around. As it is, pdfs are essentially useless and very much the non-preferred format.
Converting images from vector to bitmap is the wrong way to go; the conversion resolution is inadequate and results in mush. If you insist on bitmap, use desktop resolution, not PDA screensize.
Don't limit yourself to design decisions made years ago when PDAs had a fraction of today's memory and power.