In general, do not send attachments to the list. This is good practice for any general discussion list for many reasons. Attachments are usually bulky - formatted documents can take up to an order of magnitude more space than a text version of the same document. Most of the conference brochures, job announcements, etc. that people send around do not really need special formatting. A 150kb word processed document may take up only 20kb or less as a simple text file that can be pasted into the body of your message.
Most messages only appeal to a small segment of the entire list.
People don't get too irked when there are a few small messages a day, but large attachments take up space and pose a risk to a majority. As some have already suggested - the best way to handle large documents and documents that can't easily be turned into text is to offer to send it individually to those who are interested. Rarely will you be inundated by requests. It is fairly easy to set one of these up on the fly, upload your raw document, and then pass the URL onto those who want it. Many of these sites also have free on-line Web authoring software, and if all you want to do is make a page with a simple link to your documents without fancy graphics or coding, you can make a basic Web page in a few minutes that will allow others to view or download your document with a mouse click.