There are three current Nikkor 50s: the 50mm f/1.8 AF-D and the 50mm f/1.4 AF-D and the brand new 50mm f/1.4 AF-S G. The 1.8 and the 1.4 models are over 20 year old designs, and have clunky, 7-sided diaphragms,and have basically, horrible bokeh. On a scale of 1 to 10, both render bokeh at about a 3, just like the Canon 50mm 1.8 EF-S II cheapie 50.
But the Sigma 50mm 1.4 HSM and the new Nikon 50mm f/1.4 AF-S G are new, modern lenses, and both have rounded apertures, and both have smooth, creamy and well defocused backgrounds. Both of these newer, somewhat expensive 50's give nice bokeh. It's not so much about sharpness, he wants a lens that gives a "look". These would rate 7 to 8 in my book. On his D60, ONLY the Sigma 50 and the new Nikon 50/1.4 AF-S G will autofocus.
Some lenses have what is called a unique style of "drawing". Many Japanese photographers have studied bokeh and lens drawing; some lenses create a very unique visual impression or imprint on the images they capture, especially when used at wide apertures. It's not just about sharpness, it is about a lens that will create,as the OP requested, a *look*. A good example of a lens that creates a look is the Canon 135mm f/2 L, or the Nikon 135mm f/2 Defocus Control lens; both have sharp in-focus areas, but the transitional zones where the depth of field fades from sharp to out of focus is very creamy,and smooth,and the background is also magnified due to the long focal length, and that creates a sort of compression of distance,and causes the backgrounds to be rendered well out of focus, and can take large expanses of a cityscape or a flower garden and render it as large,pastel areas of color and light, like the OP's second example of the Japanese woman in the yellow hat,kissing the white bunny: that type of background rendition looks like a 300mm telephoto, but could also have been done with a 135mm shot at f/2.5 let's say, from 7 or eight feet on a FF camera.
Nikon's regular, old-school 50 1.8 and 1.4 AF-D lenses are not "pretty" imagers. Dscience here uses the new 50/1.4 AF-S G--it is a pretty imager.