It's like having an all-star stock-picking team in your corner.People who invest in stocks come from all walks of life and have diverse goals and values and varying levels of risk tolerance and start-up capital. That's why it's hard to come up with a single stock everyone should own. But if I absolutely had to pick one, it would be Berkshire Hathaway (BRK.A 0.44%) (BRK.B 0.57%). The Warren Buffett–led conglomerate has many qualities that will appeal to long-term investors. Here is more on this longtime mark ...