2003, A6, V6, automatic (no turbo, no quatro)
I looked for wiper blade aftermarket refill at parts stores near me (Auto Zone, Advance Auto Parts, Sears) and I found nothing to fit on my car.
To make the story short, if your wipers look like this:

with arm end like this:

and unlocked / locked wiper blade:


the aftermarket perfect fit wiper blade refill that I found is made by Valeo part # 900-22-5B:

You can buy only online (I bought from amazon.com for under $20 per piece)
Below it is the link to Valeo online catalog for other Audi models:
Product Catalog | Valeo Wipers Systems USA

 

This is good info since I have only been able to find these low-profile sport blades from the dealer at close to $30/each. thanks.