Basically, every color you need for day-to-day, back-to-the-grind neutral make-up. Which is to say, the make-up we wear the most. Laura Mercier palette, $48 at Sephora.
I don't think it's much of a stretch to say primer has changed my life. Change your friend's life for the better! Benefit Primer Kit, $10 at Sephora.
Some other ideas: A cute belt, like this bow belt from Madewell; a stack of stylish friendship bracelets (also from Madewell); fancy Butter nail polish, $14 each; comfy socks from Terrain; a super fancy Ibiza round brush for optimal blow-drying success; Ryan Gosling's abs in "Crazy Stupid Love"; and a great make-up brush set from Sephora.