Updated from 12:40 p.m. ESTEditor's note: This marks the debut of a new series of articles on TheStreet.com pitting two big companies against each other. Today, Apple vs. Microsoft. In the first of TheStreet.com's Archrivals series, Apple ( AAPL) and Microsoft ( MSFT) face off in the battle of the operating systems. Investors will be looking to see how both firms boost their sales through state-of-the-art operating systems such as Microsoft's Windows 7 and the latest version of Apple's Mac OS X, dubbed Snow Leopard. With Apple said to be unleashing Snow Leopard sometime this year, and Microsoft gearing up for Windows 7, the tech sector is preparing for a clash of the OSes.