A lot of really nice Bokeh background pictures. But there still seems to be quite a lot of excellent pictures posted that don't have bokeh backgrounds. Rather they have semi buried backgrounds. As was already mentioned, a bokeh background should have no recognizable images.
Pleasing areas of blur (good bokeh) generally have blurred edges, while less pleasing blur (poor bokeh) have firmer edges. Which would go along with what you're saying Joel, regarding recognizability of objects in the background. Better bokeh, less recognizability. But in none of the online definitions I can find, is recognizability part of the definition. As I again look through my googling for bokeh, I find that the whole subject is rather nebulous, as so much is "in the eyes of the beholder." It all seems to come down to whether one finds the blur pleasing. Some folks regard "bokeh" as only occurring in a photo when there are blur circles from out of focus specular highlights or point sources of light, but again when trying to pin down a definition, that is only one part of bokeh. I tend to like what wikipedia has to say about it. Even Ken Rockwell weighs in on the subject (surprise, surprise?), but again saying it comes down to what one finds pleasing. In my most recent googling I found a pdf article from Zeiss (linked from Rockwell's article), the lens manufacturer, that addresses focus, blur, and bokeh from pages 25 through 40-something, of a very long and very technical document. Interesting reading with lots of formulae and diagrams of light and lenses, but again coming down to the eye of the beholder.
Some general principles for achieving a pleasing bokeh: the larger the format of the camera, the more pleasing the blur; the larger the aperture, the more pleasing the blur; the longer the focal length, the more pleasing the blur.
Like Joel, I find less recognizability, and less "busy" background blurring to be more pleasing, but I wouldn't say that examples that aren't that way aren't bokeh.