I have set up a POP3 and gmail account on nexus 7, but I can't find any option to save email attachments. I didn't see anything in my account settings nor any choices while receiving an email with an attachment.
Save my Attach is a usful utility app that can download any sort of attachments from Gmail and the stock Email, including picture, MP3, PDF and etc. After instlled on the tablet, just open your mail app, touch the preview button, and select "save my attach" option from the pop- up lists. Then you can also rename the file.