The CHDK is an open-source firmware for Canon cameras. It’s only loaded temporarily via the memory card, does not void your warranty and gives you a programmable digital camera on the cheap. You can do many cool things with it, including full control of exposure/aperture/ISO/focus, bracketing, motion detection, custom OSD interfaces and more.
I’ve been eyeing an Olympus E-450 (with a Zuiko 25mm “Pancake” lens), which is a fairly compact dSLR, as my next camera. I think CHDK doesn’t support any dSLR models yet, so I’ll probably have to get another point-and-shoot if I want to play with it. Damn you, Canon!
The wiki has a page with a lot of SD memory benchmarks, sorted by camera model. Useful for the next time you buy an SD card.