I have just enjoyed 4 days of scent shopping in Vienna, Austria.
After exhausting my feet and my nose, my wife and I were careful to recall stores and locations to add to this thread.
1. DOUGLAS. For good mainstream scents, Douglas is a good first port of call.
http://www.douglas.at/
There are several stores in the city center but their megastore in Kärntner St. is a sight to behold. It has 2 floors, with the bottom floor dedicated to fragrances and cosmetics (incl some rarities!), and their mezzanine boasting an impressive
Acqua Di Parma boutique which sells scents and AdP leather goods!
2. NAGELLE & STRUBEL. Within comfortable walking distance of the Douglas superstore Naegele & Strubell is located next to a tall ivory/gold coloured statue in the main mall at Graben 27.
http://www.naegelestrubell.at/
This is a fantastic store which sells many mainstream brands, but also an equally large variety of Niche and hard to find labels. Eg:
Etro, Ranc'e 1795, Carthusia, Bond No.9, Keiko Mercheri, Miller Harris, Penhaligons, Floris, Santa Maria Novella and many many more.
3. LE PARFUM. Our favourite Austrian scent store by far!
www.leparfum.at
Located approximately 30 meters around the corner from Nagelle and Strubel in Petersplatz 3, Le Parfum is a niche enthusiasts dream!!
The store is small, but the range is fantastic. You can find
Serge Leutens, Clive Christian, Carthusia, Armani Prive, Amouage, Goutal, MPG, Villoresi, Caron, Penhaligons, Tom Ford, Bond No. 9, Dior Couture Colognes, E. Coudray, Floris, Rancé, Washington Tremlett, Ombre Rose et al...
Please see the thread titled "REVIEW: Le Parfum -Vienna" for more...
4. MARIONNAUD. A good fragrance franchise with mainstream scents at good prices.
http://www.marionnaud.at
Also with several stores in the city (eg: Graben close to the H&M store), Marionnaud offers a good range. We managed to find several great deals on Hermés, ST Dupont, Lanvin and some Etro.
Hope this helps the enthusiast roaming the streets of Vienna!