A few questions first. Don't you love opening your email client and having to wait 5 minutes just to check your messages because some !@#$% decided it would be cool to send you a 10 MB funny video? Why use our server to send large attachments and make it work more than it needs to? Let's just make attachments easier on everyone. Also eliminate waiting time by uploading to the server, then just having it returned to you because it is too large. Try some of these sites.
http://wwww.sendthisfile.com
http://www.filefactory.com
http://www.mediafire.com
http://files-upload.com
http://gigasize.com
http://pando.com
http://xdrive.com
Look at the FAQ's to find out your restrictions and limitations. But, this will eliminate the email waiting game and you will no longer be pegged as having bad email etiquette. Your recipients can download - or not download - whenever they want.