Each language I've used has had its pros and cons, but some features have really shone through as being indispensible, shining examples of how to design a programming language to make programmers happy.

I use PHP a lot at work, and the one thing I really miss when moving to other languages is PHP's foreach:

foreach($items as $item) //iterate through items by value
foreach($items as &$item) //iterate through items by reference
foreach($items as $i => $item) //by value, with indices
foreach($items as $i => &$item) //by reference, with indices

In C#, I'm kind of smitten with the built-in multicast delegate system, as well as the way it handles getters and setters.

So what's your favourite/favorite language, and what feature makes it awesome?