I have had bikes all my life, I used to BMX race then moved onto freestyle trick bikes then went into trail riding so I owned every price range of bikes so i will tell you that for the most part it comes down to what you want to do with the bike and just test riding and finding what feels good to you!! Also when you go look tell them you might want to do some trail riding BUT give them an idea of the type of trails you are talking about. If you want to look into Treks see if you have a Trek store near you that is how I got my last year's model for cheap, you might pay more but they have a great warranty. I ride a Gary Fisher 29er which is a hardtail mountain bike BUT unless you plan on getting really frisky with trail riding you would not need anything like mine... My idea of fun riding is stuff like this
