Lately I have become interested in the broad world mountain biking. My primary interest right now is primarily along the lines of adventure bicycling (ie, Great Divide trail type riding) but old-fashioned single-track riding holds some interest as well.

My current bike is probably sufficient for quite a lot places I might ride but I really want the versatility, stability and ability to use 29'er tires that a MTB offers. The two MTB's at the top of my list are the Ogre and Troll.

I know both bikes have suspension corrected geometry (80mm-Ogre/100mm-Troll) and it's possible I might want to add a suspension fork at some point down the road. However, I know absolutely nothing about suspension forks. When I purchase something I shop for value-for-buck deals so I won't buy an inferior product that is inexpensive but I also generally don't buy top of the line either. What is a realistic price-range to add a good, serviceable suspension fork to either bike? What are some examples? Is 80/100mm of travel even worth messing with and what type of terrain would generally call for this level of suspension?

Thanks! I look forward to learning more about this area of mountain biking.