Dan, I do a fair amount of FM listening and haven't found anything better in an indoor antenna than the basic folded dipole made from 300 ohm twin-lead. A few years ago I tried an amplified antenna of the tall thin pyramid type and another shaped like a plate, but overall neither was quite as good as the simple dipole. There's a rather entertaining description of adventures in FM antennas
here with a section of tips on making one. Another how-to article is
here . So, I doubt that any of the Terks or similar are worthwhile.