Like Morkula said, the highest you can usually get is really not that high, and that won't even be enough to cope with inflation (depending where you're from).
So let's say you're a random American and you decide to invest in a bank with a 2% interest rate annually. Great, now you can sit back, relax, and watch your money grow, right? Wrong. The inflation rate in America is 3.33%. This means you not only not earn anything, but you actually lose 1.33% of your purchasing power.
So basically, banks are a really bad idea for long-term investment. They're there for transactions and emergency funds, but definitely not for retirement plans.
Trading is super risky, although that's what my old millionaire friend did. I do stocks too, except I do it differently. Instead of buying and selling every day for four hours straight, I do it once every other month for 30 minutes. It works much better than trading.
That's good, be sure to do it right though :D