AndFTP

AndFTP is just what you'd think it is: an FTP client for android. No real bells and whistles, just straightforward FTP. If you leave a computer running at home, and have five seconds to forward a port, you can enjoy all your files on the go. I've found it useful for grabbing PDFs I left at home, or quickly grabbing a song that's stuck in my head. Haven't really found a need for uploading anything as of yet, but I suppose it's good to know that I can.

In the interest of security, I would recommend using SFTP by enabling SSH from the "sharing" preference pane of OS X, and forwarding port 22 to whichever computer into which you wish to remote. If you're terminal savvy, this has the added advantage of allowing you to SSH into your computer—a feat also easily accomplished from your android phone.