good for you....I am glad that you are enjoying biking....
I would go with Kona Hoss or Hoss Delux...you can find the 2006 modesl for great end of season sale price right now. Contact your local Kona dealers.
My second pic would be a well equipped Specialized Rockhopper.
The reasons I vote for Kona Hoss are (keep in mind that fit is the first and most important determinant):
1. Materias and frame design: Kona uses a 7000 series aluminum which stronger than 6000 series (though a bit heavier). kona frame geometry is great for almost all kinds of riding. you have to ride the bikes for understanding the difference.
2. Kona Hoss is designed for bigger riders. and I think it would be more adative to the needs of a bigger rider.
3. Kona frames are well known for durability. So, your $1000 (or less, if you get it on sale) would go a long way, cause I think you will be able to use the frame for at least next 5 years.
Rockhopper is another great bike for general usage. I dont like the Hardrock, its very clumpsy.
The third option you may want to consider is an Iron Horse. They are a small company, but they offer one of the great values in the market.
Warning: at $1000 price point, I would stay away from dual suspension bike. you would get a lot of bike for that money if you go with a hardtail or front suspension bike.
good luck