Since being at uni and doing all this science stuff, still my favourite picture i have seen is this.
This is the Eagle Nebula which is a young cluster of stars about 7,000 light years away. It looks like some little jet of smoke or something but actually its 4 light days high, thats like 100 trillion km. You can see so many cool things happening in this photo, top left are shockwaves from other stars which send ripples through the matter which make it start to gather and create new stars. On the top at the right there are Pillars of Creation where new stars are already being formed and that big pillar is made up of dust particles smaller than that around the house at home.
ITS JUST SO FUCKING COOL. I need more stuff like this to remind me why science is cool.