The best DVD shop for TV series at Mariahilferstrasse in Vienna?

Hi everybody,
next week I'm gonna travel around the most beautiful cities in Europe so I'll go to Vienna. I'll be there just for two days and most of the time I will go sight-seeing (because there really is a lot to see) so I won't have much time for shopping. I want to buy a few TV series on DVD, because in my country (Bulgaria) there aren't a lot of them. I've heard that man can find everything at Mariahilferstrasse, because this is the best street and there are hundreds of shops for everything. Can you help me a little and say if you know which is the best shop for TV series there, so I could save two or three hours of searching and use that time to see more of Vienna?
I will be really, really thankful if you can help me :)
There are three stores I can think of now: Saturn (Mariahilferstra??e 42-48)
M??ller (Mariahilferstra??e 97): don't be mistaken when you see it - only the basement is a drugstore, there is floor with CD's and DVD's and a lot of TV-Series. And then Cosmos (Mariahilferstra??e 120), but I have not been there for a while.
I'd start with M??ller - I saw the best deals there in the past, then Cosmos and last Saturn. Of course there are other places in Vienna but the idea to look for it on the Mariahilferstra??e sounds fun (but horribly crowded on Saturdays)