I wasn't going to add templates to D until I figured out a way to make them simple.
The syntax for inferring a type for function calk arguments is nifty too.
Lastly, today I finally understand what mixins are , I just read some stdlib file somewhere and thought, wow that's rather useful. I definately think I will be making use of mixins sometime soon, been working on a small compiler in D itself and there are times were duplication (or perhaps inclusion is a better word) of code would be nice in such a manner.