Kind of unimpressive. Seriously, go check out pictures of his houses in California and Sag Harbor, where he wrote his great works like Of Mice and Men and The Grapes of Wrath. Apparently, he wrote East of Eden in New York, but in a house that no longer exists. The only events of note that happened at this address are Steinbeck's fall from a second-story window that resulted in a year walking with a cane and a divorce from his second wife, Gwyn (whose son wrote Jaws).
However, Steinbeck did have some interesting, conflicting thoughts on New York, which he published in "The Making of a New Yorker":
"Every once in a while [Gwyn and I] go away for several months and we always come back with a 'Thank God I'm home' feeling. For New York is the world with every vice and blemish and beauty and there's privacy thrown in. What more could you ask?"
"New York is an ugly city, a dirty city. Its climate is a scandal, its politics are used to frighten children, its traffic is madness, its competition is murderous. But there is one thing about it-once you have lived in New York and it has become your home, no place else is good enough. All of everything is concentrated here, population, theatre, art, writing, publishing, importing, business, murder, mugging, luxury, poverty. It is all of everything. It goes all right. It is tireless and its air is charged with energy. I can work longer and harder without weariness in New York than anyplace else…"
But while living at this address, he wrote in a letter, "New York is a wonderful city. I'm glad to be putting down some kind of roots here. It is going to be the capital of the world. It isn't like the rest of the country--it's like a nation itself--more tolerant than the rest in a curious way...neither good nor bad but unique."