I notice that medium roast is trendiest among the snobs right now. Some shops won't even serve dark. I understand that dark roasts can verge on one-note, but personally I like coffee to taste like coffee. Often times what the shop serves is so lightly roasted and brewed they practically taste like tea, with no body. It's fruity and acidic, which can be a little more varied, but personally dissatisfying.

For espressos, the full-city / medium-dark roast is maybe my favorite right now, and for other brews anything between a medium that's a little on the dark side and a dark roast. Acidic is fine, but it needs that body and deep flavor.