Bloomberg/Getty Images Gary Shilling is predicting a recession and a steeep stock plunge by year's end. The top economist said a downturn was almost inevitable, as consumer spending is likely to decline. He sees the S&P 500 dropping as much as 30% as stocks get punished for inflated valuations. Gary Shilling thinks there's almost nothing that can stop a US recession this year. The legendary economist and Merrill Lynch alum laid out a grim outlook for markets and the economy in an interview...