I had a hybrid (Specialized Ariel Sport) which I had hoped to ride both road and mountain. Unfortunately, it was not good at either.
If you mountain bike, go for either a hardtail or a full suspension mountain bike. Hardtail is cheaper and lighter.
Even though I have a full suspension Santa Cruz Juliana, I am eyeing a hardtail myself.
2014 Liv Lust
2013 Specialized Fate Expert with carbon wheelset (sold)
2012 Specialized Amira Elite
2010 Santa Cruz Juliana with R kit and Crampon pedals (sold)
2011 Specialized Ariel Sport,suspension post,Serfas Rx Women's Microfiber saddle (sold)