Almost 5 years ago I picked up one of the first Voigtlander 25mm f/0.95 lenses in Australia and I have always wanted a great ultrawide manual lens and at last there is one. Not the Voigtlander 10.5mm f/0.95 (which hasn't started shipping yet) - that won't be wide enough. I now have a Kowa lens in my kit.
I first came across Kowa lenses 40 years ago playing with Kowa anamorphic lenses for cine photography and projection and I knew they were fantastic quality. When the Kowa Prominar 8.5mm f/2.8 turned up on Mainline Photographics site, a few enquiries and a chat to Scott and I decided to go for it. I expect it will be cheaper than the Voigtlander and the extra 2mm makes up for the loss a bit over 3 stops in speed (OK, it doesn't).
Here is an example from the lens...
Mitchies Jetty II 5 _S by peterb666, on Flickr
I have stopped this down a bit (it is probably f/8) to get maximum depth of field.
I have also written a review of the lens which you will find on my blog site...
EDIT:(hyperlink fixed) Peter's Kowa Prominence 8.5mm f/2.8 review