Earnings by definition are after all taxes etc. Some analysts will exclude one-time gains or losses from a quarterly earnings report when computing this figure, others will include it. For example, if Amgen has a lot of products in the pipeline, I wouldn't mind paying a large multiple of its current earnings to buy the stock.
PE is a much better comparison of the value of a stock than the price.
Second, it's useful to look at the forward and historical earnings growth rate.