Natron

Natron is a digital compositor for VFX and motion graphics. The node based engine suits my background in software engineering.

Whether you expect to be performing any Visual FX or not, it is worth looking at a few Natron tutorials as they'll give you some background into some of the basics for animation and editing. Open Visual FX is a good source of information and the Compositing in Natron video tutorial is a great place to start.

Tip: Natron can be quite overwhelming to the beginner. The merge node will feature in your graphs - the main image/source should be connected to the B (base) input and the images/sources to merge in should be connect to the A inputs.