The Hubble telescope is always a source of joy and glee for me, especially their 3D flyby videos created using actual images and data. Now you can see them all in one single gallery and feel like a little kid looking at the universe. Here are the very best clips.
If you have 3D glasses, you can see it in 3D too:
Bright Pillar in the Carina Nebula
Hubble extreme deep field
Moons of Saturn
Active Galaxy Hercules A: Visible & Radio Comparison