Speaking of Email, there are certain emails that I get forwarded to me regularly (travel documents). They're forwarded as an email attached to an email, and neither GMail, nor Outlook, nor Outlook Express, nor Eircom.net, nor Windows Live can actually properly open the attached email to let me print it. But guess what can? YAM on the Amiga
So I open them and forward them back to my GMail account for printing.
YAM is excellent if you wanna try it, its limitations however are that it can't display HTML mails (though it can open them in a browser for you), and it has no IMAP support so it's POP3 only. But other than that it works great and has a huge list of features that give it quite a lot of power. As for attachments, it depends on what they are. Things like images and sound files are no problem, though large images are slow to decode on a classic machine, and video is generally ruled out for the same reason. Where you have the problem is things like Word documents and Excel sheets, and that's more than just a datatypes problem - you really need an office package with support for modern file formats to be able to open them.