DPI:

Where do you get content?
Found footage
Shoot it
Use live
3d or animation
Where do you find it?

Hal Eagar:

For my own designs I will tend to try and create it as much from scratch as possible; make it from whole pixels as it were.  That way it's less limited by what you can find, and it all matches a common visual style.  What that means 3D or 2D animation mostly, a lot of 3DS Max, VRML, and Flash.  The big problem with that approach is that it takes so much time that what you get limited by is your own time, but maybe that's always the case.  And sometimes it could be just 3D or vector art but often I use lots of photos, and they are 95% found materials as opposed to shot myself.   I also like to try and keep the animations procedural, and data driven.  Puppets really, that way you can make as much as you need on the spot.  

But again that's a lot of work.

I also like to work with live video, because you get to make it every night like the puppeteerd animation, and you can make as much as you need. 

Or I like someone else to be bringing in all the video and I put it together, then the design is in the where when how, not the what.  I really feel it's mostly their design then, particularly because they probably have an idea of where and when they want to see it.  But I still really enjoy that process.

DPI:

Where do you find it?

Hal Eagar: 

The pictures, just an old web search generally does. The rest I guess comes from my head. But in a majority of the cases I'm working with a videographer who is providing video clips as well, and where those come from varies for each videographer, but I feel that they are mostly shot specifically for the piece.