I've devoted virtually an entire screen on my mobile desktop to core and third party widgets that allow me to quickly adjust phone settings, such as turning on wifi or turning off GPS. With this app though, I needn't have bothered. Quick Settings presents itself as a permanent ('Ongoing') selection in your Android drop-down notifications, and you can set it up to appear as a pop-up on top of whatever else you might be doing.
It displays free storage on both your phone and SD card, your battery percentage, and has switches and links to the OS settings for
- screen brightness
- sound, vibration
- all six volume controls and a master too
- APN (data network) settings
- screen timeout
- airplane mode
- auto rotation
- unlock pattern
- camera light (if your phone supports it and/or is rooted)
It looks great, can be customised (both visibility and ordering of the switches), has a small footprint and is free!