Well, after showing up with a gift basket, it would seem rather prudent to conquer the language barrier (Assuming they aren't telepathic), and once achieved, I think we would be doing them a great favor by sharing the cautionary tale of earth (Assuming they are virgins to the calamities we so often inflict on ourselves). Our past history reveals that when early explorers encountered new civilizations, we have always felt the need to change them into us, and we all know how that's worked out (cough, cough, Hawaii, Native Americans, Aztecs).
It would be extremely interesting to learn of their morals, values, philosophies, strengths and weaknesses, and not contaminate them with ours. It would certainly be an interesting study that would surely eclipse anything science has had the privilege of examining on earth. What they consume, how do they reproduce, what interests or entertains them, modes of transportation, and if they would care to share, how in the blasted world have they figured out ways to get along with each other.
Upon hitting the trail for home, I think it would be fitting to leave them with a little Chuck Berry music, dark chocolate brownies, and a bottle of Napa Valley Chardonay, and hope like hell they take a different path to the future.