Steam is the best software ever i buy all my games on there and wont be buying the DVD's for as long as i can imagine. I've got nearly 50 games now on steam and the beauty of it. Is that none of them need discs to be inserted it is so easy to buy everything too. The fact you can log in anywhere and download your games wherever you are is amazing as well.
The best software ever? So why is it better than say, Impulse? You can download your games where ever you are from that as far as I'm aware but it's hardly frigging amazing.