Niche Designer

I am loving this keyword difficulty tool. You type in a keyword and it will tell you how difficult it will be to rank well in that term. And instead of confusing numbers, it gives you an answer in graphical format.

You can try it for yourself below:

This site also has other neat tools like the google cache dance, which will let you see when the next update of your cache will happen, or you can check to see if you are banned by google.