I have my 42" mounted to a brick fireplace (which never gets used as such) using one of these:
Flat Panel HD Mounting Kit - Flat Panel Wall Mounts - Z-Line Designs
It's a little more on price I think but it came with EVERYTHING needed and was a very high quality everything. I liked it a lot, it's pretty secure but easy to change if needed. Plus the install was easy as well. You do need a bit of handy skills but assuming you have those this should be no problem.