🚀 go-pugleaf

I have created art in Illustrator 8 and viewed a saved pdf in Acrobat 4 under OS9. I also tried saving a pdf from Illustrator 9 and viewed it in Reader 5 under OSX. I then created art in Illustrator 10 and viewed it in Reader 5 under OSX. Lastly, I tried writing a ps file from Illustrator 9 and writing a pdf from Distiller 4. In all cases, the art appears aliased in Reader or Acrobat. The art does smooth out in Reader 5 when I flip on the smooth graphics preference. The real stumper, however, is that I received a pdf from someone else and it previews perfectly smooth while the smooth linework and text option is turned off in Reader 5. What is the deal? I just want everyone, including myself to preview the art as anti-aliased and not have to worry about a client's preference being set correctly. What is the trick? 

thanks.