Looking forward, if you plan to play with some 3.3v components, you may want to consider
a different arduino board like the seeeduino.http://www.seeedstudio.com/depot/seeeduino-v221-atmega-328p-p-669.html?cPath=132_133&zenid=f353551d840948a31981c7e0cdf81134
It is fully compatible with the official board, but has many added features
like switchable 5v vs 3.3v power.
It is a much better alternative/value than the official arduino for those that want to use
3.3v or create their own custom shields using proto/strip boards.
The standard arduino connector spacing is incompatible with standard proto/strip boards
but the seeeduino has both sets of connectors, so you can use both standard arduino
shields or standard proto/strip boards.
If you are looking to save money by making your own shields, the seeeduino, can
quickly pay off in the long run.