Ok, thanks guys. I guess when it warms up a bit I will see if any LBS offer demo's and try out a hardtail vs. full suspension. In all honesty, I don't know how much I will mtb so I'd rather not spend a fortune.
What is your targeted price range? You can get a decent hardtail for cheaper than $1000. The only problem with a hardtail is that it can be uncomfortable on your back & arms in technical parks like Allamuchy & Mahlon on longer rides. (Since I went Full Suspension, my back and arms are a lot less fatigued and I can ride longer.) However, in a park like Lewis Morris or Kittatinny, a hardtail is a great choice.
I would recommend a bike with at least an LX level rear derailleur. LX is approximately the Road Shimano 105 level and it is reliable. You really don't want anything less because it is no fun when your bike is shifting badly in the woods. Mountain biking requires a lot more gear changing and power on demand with some short bursts of power to climb up over things. You definitely want your bike to shift correctly and accurately.
One of my co-workeris is an avid road rider -- I lent him my Giant NRS at the end of the summer to try and he loved it. He was amazed at how peaceful, tranquil & at other times, intense riding in the woods can be.
Me -- I found myself on the opposite end of your situation, I just got a road bike this past season. I bought myself a Giant OCR2 -- not the bottom, but not too expensive either. I didn't think I would like it, but I do. (I just don't care for the cars too much.

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Have fun!