ultra wide angle lenses!

http://www.kenrockwell.com/tech/how-to-use-ultra-wide-lenses.htm

Awesome description for using ultra wide angle lenses.I already own 18-105 VR and 50mm. I am currently saving money to buy an ultra wide angle lens. The lens looks great and can create dramatic effects in the photo.
My Nikon D90 also has inbuilt editing features like fisheye, but the results not even are closer to what you get using the actual lens. I have never used that feature of my camera. Not only that but my camera has another 10 features which i doubt i will ever use.