I'm a novice when it comes to bikes, and need to buy a mountain bike that will last a couple years of constant riding. I'll be using it on the road, on trails, and in snow. My budget is $300 to $350. So far, I've been looking at bikes on ebay, and I've been considering buying a Trek 4500 or a 2000 Trek 6500. I could probably get the 4500 for around $250 and the 6500 for about $350. I'm not really sure which bike I should buy or if I should buy a completely different bike. I've heard that the Trek 6500 is a really good bike, but the one I'm looking at is also five years old. Does that make much of a difference? I only have a week to purchase a bike, so what bike do you guys recommend?