which antenna do you recommend

[jeffbeold]

Hi all,
Just bought a Samsung ln46c650, and really want to drop DISH et al. I'm at the north end of Fort Collins, Colorado, have Cheyenne, WY. about 40 miles north, and Denver about 60 miles south. I live in a wood frame mobile home, so I don't want and can't go really high up, plus I have a big cottonwood about 50 feet south. Any recommendations for the best outdoor antenna for my situation? Omni-directional would be great! Thanks all.
Jeff