This is a pretty tricky question. There are a lot of good books that focus on parts of Einstein's life. E.g., if you want to know the context of his development of special relativity (with regards to other work being done in similar fields), Galison's Einstein's Clocks, Poincaré's Maps is pretty good. If you want to get into very narrow questions about the kind of mindset he used when doing his science, Holton's Thematic Origins of Scientific Thought has some very nice essays in it. If you are interested in, say, his politics, Jerome's The Einstein File is excellent.

But for all-around biographies, while there are a million of them, most of them are total crap. They engage with Einstein mostly on mythical terms, or fall into platitudes about him being a "revolutionary" that don't really tell you very much. I asked a colleague of mine who has read and reviewed huge number of Einstein biographies what he would recommend, and he said that Albrecht Folsing's Albert Einstein: A Biography is what he would recommend, though it is not exactly the latest offering (he recommended it far above Isaacson's recent biography, which has many major problems in how it approaches its subject). He also gave high marks to Thomas Levenson's Einstein in Berlin, though it covers a shorter (though important!) period of his life.

I think it is important to understand that circumstances and events many biographers consider germane to the shaping of Einstein's life choices and life trajectory would be (and were) rejected by Einstein himself. Einstein believed the key to understanding his life, was to understand the aims, forms and progression of his scientific ideas. Marriages, children, arguments with supervisors, divorces, recognition by peers, awards, relocation, competitors are distractions of a "merely personal" nature. To Einstein, understanding the life and nature of the scientist is to understand the content and progression of his life's work.

In Einstein's own Autobiographical Notes the second paragraph begins -

"When I was a fairly precocious young man, I became thoroughly impressed with the futility of the hopes and strivings that chase most men restlessly through life. .... By the mere existence of his stomach, everyone was condemned to participate in that chase. The stomach might well be satisfied by such participation, but not man insofar as he is a thinking and feeling being."

Later it continues with the famous passage :

"It is quite clear to me that the religious paradise of youth, which was thus lost, was a first attempt to free myself from the chains of the 'merely personal,' from an existence dominated by wishes, hopes, and primitive feelings. Out yonder there was this huge world, which exists independently of us human beings and which stands before us like a great, eternal riddle, at least partially accessible to our inspection and thinking. The contemplation of this world beckoned as a liberation, and I soon noticed that many a man whom I had learned to esteem and to admire had found inner freedom and security in its pursuit. The mental grasp of this extra-personal world within the frame of our capabilities presented itself to my mind, half consciously, half unconsciously, as a supreme goal. Similarly motivated men of the present and of the past, as well as the insights they had achieved, were the friends who could not be lost. The road to this paradise was not as comfortable and alluring as the road to the religious paradise; but it has shown itself reliable, and I have never regretted having chosen it"