I'm looking to buy a new bike. I'm a beginner, but intend to dive head first into mountain biking (hopefully not literally). I'm not a big guy - just 5'9 145 pounds. I'm partial to hard tails, but would be willing to look at a full suspension. I will use the bike primarily for light-medium trails and for general fitness. In time, I would like the bike to be able to grow with me as I advance. My price range is 800-1200 give or take. I'm looking at the following bikes and would appreciate any thoughts or suggestions.

Jamis Exile (local dealer carries Jamis)
http://www.jamisbikes.com/bikes/05_exile.html

Jamis Dakota AL
http://www.jamisbikes.com/bikes/05_dakotaal.html

Devinci Phantom (local dealer carries Devinci)
http://www.devinci.com/english/phan.html

Marin Indian Fire Trail
http://www.marinbikes.com/bicycles_2...dian_fire.html

Bianchi KingBee (dealer about an hour away carries Bianchi)
http://www.bianchiusa.com/583.html