I use my PS3 primarily as a Blu-Ray player, but I'm sure Sony will kill that feature eventually as well. ;-) (And in the United States, the PS3 is heavily marketed as a Blu-Ray player. Of course, most salesmen will tell you that it can't be better than X dedicated Blu-Ray player, but that's mostly perception. Most people won't have their displays tuned to the point that it makes a difference. The image is awesome on my 55" Samsung 8500.)
A number of universities and governments use PS3s for analytical computing, but with mainstream x64 processors coming with 8, 12, and more cores, and mainstream graphics cards carrying hundreds of stream processors, the Cell (as it exists in the PS3) isn't much of a win apart from the price.