I live in Columbia off 175 between 108 and 32. I used a diplexer to feed the rabbit ears into and ran a cable along my fence to the back of my yard. Just by placing the rabbit ears on my fence and pointed per antennaweb.org, I can get near every channel. If I move them to the top of my shed (about 7 feet), I get more. I do have to re-orient the rabbit ears depending on if I'm trying to get DC or Baltimore. I've tried, but haven't found one position that gets them all perfectly.
I picked up one of those flat antennas at Radio Shack for 50 bucks with a built in amp. Can't even get above 20 on any one channel. My rabbit ears kick its a$$.
There are a lotta trees around me as well. I do think we're on one of the higher points in Columbia, for whatever that's worth.