Mountain Biking - Basic advice for newbie

Looking for MTB that is comfortable and easy to ride.
Weight: 205, 6 ft, average to below average shape, age 37
Doing some camping might have a 30 lb pack on my back.
Trails: mostly two tracks and ATV trails. Some hills, mud and sand but nothing insane, MI and Ontario
Distance: nothing over say 25 miles, probably a lot less.
Price: 500-2000 depends on advice
Skill: beginner, raced when I was 18 on a Haro Team Extreme (I think thats the name of the MTB)
Went to a shop and staff treated me like a dumb redneck
Difference of between full suspension, hardtrail, 29er's etc need to be explained. Is there such a thing as a full suspension 29er?
Not looking to race just A to B riding.
Probably will be buying online due to warm reception from local store.
Thanks.

Your price range gives you a lot of leeway. full suspension v. rigid or 26 v. 29 are really a matter of preference. I'm 6'1" and 175 and I rode a hard tale in NW lower MI quite a bit, but would opt for full suspension - nowadays it is very easy to adjust your suspension on the fly if you want it stiffer. I just rode my first 29er, a Fuji Tahoe SL (http://www.fujibikes.com/Mountain/29er/Tahoe29SL.aspx), and feel that it is a bike that takes a bit more fitness and handling skill to ride efficiently.

There really is no better way to find out what you want to ride than to get on some demo bikes. Check around to see if there are going to be any races or events in your area that will have demos. Otherwise, maybe there is another local bike shop.

Also, you might look into paniers for your bike to haul gear - it would be way easier on your back.

If you have not read this post as of yet do so, it will give you some ideas.

http://www.bikeforums.net/showthread.php?t=67259

Do as much reading and test riding as you can before you buy...;)