All around camera - birthday parties to vacations at the English Olympics

For birthday parties and vacations I'd recommend the Canon SX260 HS, the 20x zoom will be a huge benefit.

The S100 is an awesome camera, but it really sacrifices the zoom.  It does have a larger sensor, faster lens, which means it will get much better image quality especially in low light.  Also consider it if you want to learn more about photography since it shoots RAW, and has more manual controls and advanced features.