GoPro has been in the HD action sports and helmet cam game for some time now, with its Hero line proving a popular sight atop many a daredevil's lid. Now, you can add HD Hero 2 ($300) to the ever growing list of options now, as this is the latest (and they say greatest) incarnation to date. Last time we tested the Hero Original -- as it's now called -- against the Contour HD, but now we're pitting new against old, like for like, side by side. Not only will we discover how the new boy stands up against the camera it effectively usurps, we'll also see
