I recommend Bitcoin Checker (https://play.google.com/store/apps/details?id=com.mobnetic.coinguardian).
It shows prices for all different coins from many different exchanges (Vircurex, Cryptsy, MtGox, BTC-e, Bitstamp, coinmarket.io and much more). It also has an alarm function (e.g. you can set it up to ring when the rate exceeds x $/BTC) and even a TTS (it automatically announces the course all X minutes per text-to-speech-engine. There's also a widget and best of it, you can put the rates you need most permanently in the notification bar.
I think it's a great app, fast, easy and feature-rich.