Funny I saw this post, I actually have the same issue when printing PDF documents from InDesign.

when you zoom in they are normal... when you are zoomed out they look stupid... right?

I think that's just part of the compression and how Acrobat displays images. Have you tried "fullscreen" mode? Does it print OK?

My files print just fine, but when I want to send them to people on-line to review them (in PDF), even in fullscreen mode they look terrible and very unprofessional. There is no trick or illustrator function to fix it?

well, maybe actual image files would be more appropriate. on second thought though--are you formatting your PDF for screen or print (the settings for each are in the PDF printer)? The print version has a much higher resolution and may be why it looks wonky on-screen.

The has been a problem in the past. I recently purchased CS3 Professional that comes with Acrobat and it seems they have solved that it in the lastest version.

I have CS3 and I still have this problem.
It prints out what it shows in Acrobat. Am I missing a setting somewhere?

Do you have Acrobat Pro? Maybe there is a distinction betwen the Pro and less robust version of their software.

Yeah, Pro.

maybe save illustrator as pdf, rasterize pdf as jpeg, then back to pdf if you must have pdf format.

i've had many a random problem with the illustrator - acrobat pdf transition.

Even on 72dpi it looks ugly...

Flatten your PDF's into images for on-screen presentation. PDF lines are only loosely to scale when zoomed out.

I think I figured it out (for InDesign). In the print dialogue box, select PDF and select options in the left Menu. In the Images: Send Data dropdown menu chose All.

it's how acrobat compresses vector graphics for display. not much you can do about it. my advice is to take your pdf and convert it to a 200-300 dpi jpg in photoshop. use the jpg for on-screen/ppt display. use the pdf to print.