Artificial intelligence (AI) has been the biggest investing theme on the planet in recent times. Investors have piled into AI stocks -- from those creating the technology to those using it -- amid hopes AI will revolutionize both business and your daily life.Today's $200 billion AI market is forecast to reach $1 trillion by the end of the decade, suggesting major opportunities ahead for companies at the forefront. And these AI stocks have driven gains in the S&P 500, helping the index confirm its presence i ...