Hey all! I'm looking for a new bike. Most of my riding is done on city streets and bike paths, but I want the bike to hold up to gravel roads occationally. I've read a lot of great reviews about the Trek 7200FX. The bike I have my eye on is the Trek 7300FX. What's the real difference here, and is it worth the extra money. Also, does this bike fit the description of what I would use it for? (I'm trying not to sound like an idiot here, I'm a newbie--still)