These companies offer solid return prospects and above-average yields.The S&P 500 includes world-class companies with solid return prospects, but income investors might be dissatisfied with the index's current average yield of 1.3% -- the lowest in over 20 years.Some of the best companies in the index demonstrate solid business performance while also offering better dividend yields. Here are two such stocks that have what it takes to continue rewarding investors for years to come.1. Coca-ColaCoca-Cola (KO 1 ...