Despite four years on the market, Motorola's RAZR V3 is still the best-selling cellphone in the US, the NPD Group says. While exact market share isn't published, the researchers put the clamshell design above the second-place iPhone 3G as well as the BlackBerry Curve, LG Chocolate and BlackBerry Pearl in the top five. The RAZR earns its position primarily through its sheer availability, as the d