Sol Duc Falls, Olympic National Park

Capture:

This image was taken during one of my workshops. I thought I couldn't get a better picture of a rainbow over the Sol Duc Bridge than I'd gotten the previous year so I didn't bring my camera gear. Fortunately, I did have the foresight to put a CF card in my pocket and I borrowed my co-leader's Canon 5D MKII (nice camera) to make this shot.
I had several students with me and we were all crowded in close at the best spot to get this shot and as a consequence I ended up with someone's jacketed arm in the lower left corner. I didn’t discover this until after I got home.
Exposure-wise, this was pretty straightforward and the Canon evaluative meter handled things just fine. I'd note that just a few years ago with film, this picture would have been a lot more difficult due to the range of light in this scene and the limitations of slide film. Today's modern digital SLR cameras continue to amaze me with their dynamic range.

At the Computer:

As mentioned, there's a jacket in the picture. I had recently upgraded to Photoshop CS5 and this was a great opportunity to try out the Content Aware Fill feature. And boy did it work wonders here.
I think I used the Shadow/Highlights tool on a separate layer to open up the shadow areas in the lower left and upper right. I also remember using a Hue/Saturation adjustment layer to "pop" the rainbow slightly.