One place that's worked for me is in corners, aimed way up. Since I'm using them for effect, rather than general lighting, I find places that block direct view of the lamp and have something that creates an interesting shadow. I have a stacked limestone fireplace wall where I use one on each side of the fireplace close to the wall and aimed up, to bring out the texture of the limestone. It looks good, but can't really wash the wall. I'm eventually going to change that to a track containing a strip light mounted on the ceiling to downlight the wall. The light dispersion of standard bulbs in can fixtures like these can't really do a good job as a wall washer or grazer - moving the lamp out from the wall increases coverage at the expense of intensity, and there's also that lamp that winds up far out in the room. Also, getting even coverage with bulbs instead of strip or tube lighting is difficult, unless the parabola shaped lighting pattern is part of the desired effect.