I posted five way I use to come up with new stuff over on my blog. Really interested to hear what you guys do to think up new imagery in your work too!
6 Way to come up with new visual Ideas

These methods work best for me, these are what I do when I hit conceptual roadblocks, especially as they (often) occur when trying to develop color and apply color theory to my artwork. I'm glad I can share them with you guys! ^_^

1. Google image search using random keywords alluding to various concepts of interest. If stuck on a keyword I use my pet alligator widget on my macbook to do the "conjuring" for me.

2. Go to flickr.com and get lost for hours on end... "color" search is a great starting point here.

3. I walk around my house and analyze what makes me happy. Makes me ponder how happiness achieves greatness in a myriad of ways.

4. Play the rock band Muse in iTunes with the visualizer set to "Jelly"-- I normally dissolve into an existential pool of bliss, then re-emerge with Machiavellian marketing angles as they apply to art.

5. Practice Zen meditation followed by a round of Tai Chi, then I visualize the spectrum via Chakra alignment which then leads me back to the zen meditation: I go through that door thingy into an ocean of clouds and swim for what seems to be eternities. I have a lot of time on my hands it seems...

6. Try to remember my first memory, then analyze how I perceived things before I knew the words.

Thanks for posting this, Trevj, Kudos!