Thanks guys 

So if I wanted to, I could take my wallet address and private key from bitcoin-qt and import into blockchain (or any other online host which allows imports) and spend its contents??  The software (if offline) or hosting website (if online) is actually irrelevant as they are only means to send, receive and view your bitcoins.  All I need are these two pieces of information.

The other thing I haven't seen much information about is a sandbox where you can 'play' with virtual bitcoins and get to know what you are doing without risking your real bitcoins.
Does this exist?  Has anyone come across such a thing?