Thin mints are the best. However I LOVE dipping Trefoils in my tea.
Being a lifetime Girl Scout, I must say this: I've seen those prices go way way up and the quantity and quality go way way down. I'm not saying to not buy the cookies, but write to HQ and complain. The profit that goes to the troops that waive the "prizes" (200 boxes for a patch? Come on.) barely get anything back and they're making crazy big profits.
My favorite Girl Scout cookies were Aloha Chips, (white chocolate chip + macadmia), but alas, they discontinued them. So of the current cookies, I like Samoas the best.