We're renting a place at the beach with another family. I've been burned before in this situation - like pots so beaten up that they didn't sit properly on the stove. I plan to bring the pancake griddle and probably my immersion blender in case I make gazpacho or hummus. I picked up a little charcoal grill, since I haven't heard confirmation of a grill on site. For ingredients, some olive oil and good balsamic, a good knife or two, and my spice boxes (watchmakers cases from Lee Valley Tools - should travel well!).
What have you missed in such a situation, or been glad to have along?