Hi all! I've been looking at buying a bike for the past few weeks, and have things pretty narrowed down. I was looking for either a hybrid or a mountain bike.

I plan on going fairly diverse with my riding, as I did when I was a teen. Commuting 10 miles to work each day, beginner trails in the city (paved and dirt trails along a river, we have something like 100 miles of trail), probably a few ~40 mile trips along gravel and dirt roads, and lastly some riding through the mountains and camping. So, am I correct in thinking a hybrid or a mountain bike would be the best bet here? Is one preferable over the other, or is that more of a bike-by-bike difference than something that can be generalized?

Around me, there are Trek, Norco, and Giant bikes that caught my interest. The Norco Storm series is interesting, but for the most part it's the Trek bikes that have caught my eye. Specifically:

The Trek x-caliber 6 X-Caliber 6 - Trek Bicycle

And the Trek 8.3 DS 8.3 DS - Trek Bicycle
(or the 8.4, but currently the 8.3 is at the same price as the x-caliber 6)

The Marlin and Trek 820 also interested me, but didn't seem as appealing.

I'll be going to try these out in the next couple days, of course, and talk to a few LBS. But could anyone offer any input for me- whether a hybrid or mountain bike would be better? Whether one of the above bikes would be better than the other for my uses?