Okay, we have part of the equation here at least. Now we know the original is in Word - what software exactly are you using to create the PDFs? Acrobat Distiller? PDF Writer? Another app?
I ask because a friend sent me a large Word document a while back and when I asked why he did not send as a PDF he said it was because the third-party PDF utility he was using did not produce any appreciable decrease in file size.
I took the Word doc and PDF-ed it myself (with Acrobat Distiller 4) and cut the file size significantly (originally around 2Mb Word doc, cut down to about 400kb as a PDF).
The same document, had it been created in Adobe InDesign probably would have been around 200Kb when exported to PDF. My point is that some apps create more efficient PDFs than others.