I've owned two Canon Ixus (in USA are the "digital Elph") and have been very pleased with them. Somthing like this would fit your needs quite well. They're very portable and resistant, take decent pics...
Another great option, albeit a bit above your target budget, are the Panasonic Lumix DMC-ZS3S. They use Leica lenses and take great pics, better than Canon's IMHO. A friend of mine owns one of these and is very pleased. His other camera is a "big" Canon EOS, can't recall the model, and when he needs portability he takes the Panasonic without much regret
I suppose the photo experts in here will give you much better advice