I will go with trading, arbitration and participating in campaigns and bounties. HYIP to me like gambling you must time it when to go in and when to run out.
although there are so many other source of getting bitcoin for example signature campaign, faucet, gambling, lending bitcoin, trading altcoin, holding bitcoin itself, and if you have some good skill about designing then you can also make money from designing. but to me i will choose trading altcoin because from trading altcoin we have good opportunities to make good profit in a short period of time.
Unlike other ways, trading takes a very long time to conduct on the exchange and have a good earnings. Of course I understand that the waste of time pays very well, but you need to make a choice now what to do.