The 50mm F/1.4 is supposed to be a better lens. Faster AF and sharper. Of course it's 1 stop slower and the bokeh is said to be not as good. For the price of the 50mm F/1.0, you could buy a 50mm F/1.4, a 10D body, a CF card, AND a holiday to Malaysia to use the whole thing!
If you want absolutely the fastest aperture possible, maybe you should consider the 85mm F/1.2. I have handled one before and it is beautiful. It is at least superior to the 85mm F/1.8, so nobody is going to ask you why you got it.