You have to target at least 1 BTC for the start but in the long run you will realize that 1 BTC is not enough, I know not all of us can afford to raise 1 BTC for the future investment because that is still a big amount of money for the majority but for future investment I would say it would not change your life.
yeah you cannot do much with bitcoins, and if you are hoping to get rich with 1 btc then it will never happen as we don't know what value it will hold in future.