My favorite so far: 20 = jsf-white-bg.png: very high recognition value, while still being clean, and it will also work on b/w (without the shadows)!
Minor changes I would propose - as the creator, is open to that -:
- remove the dot of the "j", which gives it even more of the wave/upward trend
- use less shadow (or none)
- for the non favicon case, extend the area under the logo, and add "Javaserver Faces", this would also make it possible to use a straight J (just like the for the f)
- use another color, blue is the yesterdays orange, which is the tomorrows darkgreen