Almost always previews, interviews (and possibly media) for me. I nearly always have my mind made up a long time (maybe even a year or two from release) and follow the development as it moves along.

Occasionally, I use reviews to make a final decision but that's pretty rare. I don't think reviews are bought in the main - like everything, there are good reviewers and bad.

Haven't read a game box in years (and I prefer downloads, anyway).