Ecclesiates was either written by King Solomon or else inspired by him (I think the former). He was basically given everything that the world has to offer in his day. There was a general peace, he had tons of money and built beautiful buildings, he had literally thousands of women to please him. Ecclesiates is him looking back on his life at the end and realizing -- who cares? He had lived according to the Scripture a good chunk of his life for himself and his pleasure -- and received nothing in return at the end. Apart from God, he found no meaning to his life. Ecclesiates is the ultimate comment by the Scripture on what a godless life yields -- vanity, emptiness. You have to keep that in mind while reading it -- he was saying that life without God, spent on oneself (pleasure or work, hard or soft), was meaningless.
That's what I came to understand after a few readings. I have to say that I think I have finally found the door welcoming my uncertainties and also offering explanations. This realization, offered also in this book, has affected me deeply. Thank you Jeff for offering your thoughts.