Retail behemoth Wal-Mart (NYSE:WMT) defied logic for yet another quarter, posting mid-single-digit sales and earnings improvements. It's funny how a company with close to $350 billion in annual sales keeps chugging along with such little respect reflected in its stock price.

Wal-Mart posted an 8.3% increase in first-quarter total sales, even though same-store sales at the namesake stores slipped into negative territory at -0.1%. Total international sales advanced an impressive 18.5%, while total sales at the namesake stores and the Sam's Club membership warehouses both advanced a respectable 5.6%. Sam's Club comps jumped 4.7% (excluding fuel), suggesting that head-to-head competition with archrival Costco (NASDAQ:COST) is working out for both warehouse chains.   

Overall quarterly results were definitely respectable, but the stock continues to hover around the $50 range, as it has for close to eight years now. Yet over this time frame, sales and earnings have grown double digits -- an impressive streak for any company, but even more astounding for a firm as large as Wal-Mart.

Investors appear constantly fearful that domestic growth prospects will finally dim and numerous public relations blunders, stemming from questionable employee firings and health-care benefit concerns, will eventually derail Wal-Mart's stellar operational track record.

But so far, Wal-Mart has been able to overcome a maturing domestic store base and other industry- and self-inflicted challenges. At about 13.3 times forward earnings and continued strong cash flow generation prospects, Fools may want to consider placing some shares into their investment shopping baskets.

While other potentially dazzling prospects may be found at retailing rivals such as Kohl's (NYSE:KSS), Dick's Sporting Goods (NYSE:DKS), or Best Buy (NYSE:BBY), few will be able to match Wal-Mart in "saving people money so they can live better," as it has done here at home for decades and will increasingly do abroad.

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Wal-Mart is a Motley Fool Inside Value recommendation. Best Buy and Costco are Motley Fool Stock Advisor recommendations. Try any of our Foolish newsletters free for 30 days.

Fool contributor Ryan Fuhrmann has no financial interest in any company mentioned. Feel free to email him with feedback or to discuss any companies mentioned further. The Fool has an ironclad disclosure policy.