Not sure what you mean by 'Showcase' I assume you mean something to get noticed. In which case it is worth remembering that there is a huge number of sites out there. A number of people use the photo based social networking sites like ipernity, zoomr, or flickr.
Flickr is the dominant one as it gets most of the eyeballs, and has some nifty searching facilities. Remember though that there are over 5,000 photos being uploaded to that site each minute. So you have to work on the social aspects of the site to build up a following etc.
My photos are linked to from Universities, biologists, government, and UN sites, and I've had requests to license from a number of commercial organizations (though I always refuse such requests).
As a result of the academic links my flickr pages tend to come up fairly high in the google rankings, and I get somewhere in the region of 2000 hits a week.
OTOH the recent photo-blog I started gets around 30 hits a week:
http://professor-moriarty.com/moriar...land_churches/
might be the subject matter though.