True to its name, MyRegion is a regional version of Navigon MobileNavigator, which is widely regarded as one of the iPhone's best GPS apps (an opinion I share). And let's face it: Most of us do our driving within the same chunk of the U.S. (if not the same state).
If you do end up taking a cross-country road trip, it's not a problem: You can purchase and unlock other regions right inside the app.
Like MobileNavigator, MyRegion offers more navigation features than I can list here. The highlights: text-to-speech, integrated Google search, location sharing via e-mail, in-app iPod controls, and optional live traffic updates.
Given that MobileNavigator sells for $79.99, MyRegion is a steal at $14.99. You need an iPhone 3G or 3GS to run it.