What do you think of Wal-Mart, the No. 1 company on the Fortune 500 list this year? Should it be No. 1? Have you worked for the company, or bought its products? And does big mean better? Tell us what you think. The best replies will be published here, and possibly in a future story on CNNMoney.com. And if you’d like to submit your photos and video, please visit the Fortune 500 iReport submission page.