So, I had trouble getting my Epson Workforce 520 printer working on Ubuntu.  Ubuntu recongized the printer and even allowed me to install it recommending drivers, etc.  But whenever I tried to print something, the printer would just spit out blank pages.  Natty promised to download the propriatory drivers from Epson's website.  Well it does but unfortunately doesn't allow you to choose the new driver to use!!  

So, here's how I did it.  

First, download the driver from OpenPrinting and install it (download the appropriate 32bit or 64bit deb for your system).

Now, open a root terminal or become root (sudo su).

cd /opt/epson-inkjet-printer-workforce-525/ppds/Epson

gunzip Epson-WorkForce_520_Series-epson-driver.ppd.gz

Now, we are going to install the printer via Cups Web Interface so open a browser and browse to http://localhost:631.

Under the middle section, CUPS for Administrators, click Adding Printers and Classes.  

Click the Add Printer button.

After CUPS searches and finds your printer, choose the desired printer and click Continue.

Note: If you are installing the Epson via the network (wifi), there will probably be two printers listed that looks something like:
EPSON42B519 (WorkForce 520) (EPSON WorkForce 520)
EPSON WorkForce 520 (EPSON WorkForce 520).  

Choose the EPSON WorkForce 520 (EPSON WorkForce 520).  When you click Continue, the connection for the printer should be something like "lpd://192.168.1.25:515/PASSTHRU" (with the IP address of the printer of course).  If it is not, go back and choose the other.

Near the bottom, choose to manually select a PPD file beside "Or Provide a PPD File."  Browse to /opt/epson-inkjet-printer-workforce-525/ppds/Epson and choose the file, Epson-WorkForce_520_Series-epson-driver.ppd.  

Click Add Printer, set your printer defaults, and you're done!  The printer should now show up and be ready to use.