In a flurry of announcements yesterday, venerable GPS manufacturer Garmin announced the StreetPilot 2730, the StreetPilot 7200, and the StreetPilot 7500, each with XM Satellite radio, weather, and traffic capabilities. More details after the jump. Add a subscription to XM and you have weather, traffic, and music along with your navigation. So, why 3 new models you may ask? Well, it's simple (more or less), the 7XXX series uses a monstrous 7" LCD display that's designed for "larger vehicles such as RVs, semi-trucks, and buses". They're a bit huge for a little car, but look gorgeous. As you would expect …