One of the cool things about Geocaching is that people get very creative with the cache's that they put out there.  For traditional containers, by far the best is the ammo box.  There is just so much cool stuff you can fit in them and they are virtually indestructible.  The downside is that due to its size, it is harder to conceal.

There are also, many different types of caches.  The most abundant is the traditional cache.  You also have the multi cache, virtual cache, earth cache and on and on.  My new favorite is the webcam cache.  I have only seen one of these in Northern Ireland and it is in the Belfast City Center.  If anybody knows of any other, please let me know.  If yo don't have a smart phone, you will need to seek the help of a friend to take a snapshot of the computer screen with you in the cam like below.