Camera Genius Quick and easy built in camera replacement which features zoom, sound capture, full screen button, guides and anti-shake. Almost identical to GorillaCam which is also an acceptable substitute.

Pro HDR You ever try to shoot something in front of a blown out sky or window. This app has you take two pictures, one exposed for the darkest part and one the lightest and combines the two. Just make sure you don't move much

Pano Quick and easy panoramic picture taker and stitcher.

Night Camera While it would be easy to pick this app for it's name(it's takes decent pictures in low lighting), I like this app for it's other modes. Most of them can be found in Camera Genius and Gorilla Cam however it also has a 3D mode which allows you take red/cyan 3D images for use with 3D glasses. Kinda gimmicky, but it actually works and it's kinda neat.

TiltShift Generator - Fake Miniature This is easily my favorite photo enhancer....Mainly used to imitate the "toy camera" look, I found it can also be used to just super stylize images and give interesting depth of field.

Photogene I waffled on putting this or PS Mobile, but in the end I went with the photo editor that had the more robust features over the name. Can do most everything you would need for quick and dirty picture clean up including crop, color correct, frames and treatments.

Color Splash This app does one thing and does it well...allows you to take an image, turn it black&white and then selectively(with your finger) bring color back to selective parts.

QuadCamera - MultiShot Takes 4 or more shots successively and then lays them out in different grid styles. Fun way to capture action

Mill Colour This is a last minute addition, but this app seems to be a very robust color corrector. It allows you to adjust things such as gamma, gain and saturation on each R/G/B channel as well as the overall image. It also contains a hand full of nice preset "looks". Good for extra fine tuning of images above and beyond the typical color correction apps.