A low valuation doesn't inherently mean a stock is worth buying, but it certainly doesn't hurt the bullish case.How much does a stock's valuation matter? Most investors will at least look at the metric. By and large, however, most investors also know there's not much correlation between a stock's price (relative to earnings) and that ticker's performance. Expensive stocks can and do continue to rally, while cheap stocks are often cheap for good reason.Sometimes, though, a bargain is too good to ignore -- ev ...