The first Boston is essential, you should definitely check it out. And while they did stick to a similar formula after that, I think the other albums (up to Walk On, haven't heard their last two) are worth checking out too. There are lots of great songs that came after the debut (Amanda, Don't Look Back) and even though they never came close to topping the debut, they still put out some quality music. Unfortunately there was so much delay between albums that they never really had a chance to develop any sort of sound. Talk about a band with unfulfilled potential.