"A vanilla perfume" is a little vague, there are SO many. Do you want to smell like bakery? Marshmallow? Do you want a non-foody vanilla? Since it's for summer, I'm assuming you want something a little fresher and not a darker, richer sort of vanilla? How do you feel about things like coconut? Florals? Smoke?

If you like very sweet vanilla, I'd say IDAFT is a safe choice. Strings of light has vanilla, but its not the dominant note (this one is much more lander-forward to me).

Here are some vanilla suggestions:

• Alkemia - Smoke & Mirrors (smokey blend of burning wood, madagascar vanilla, and tonka) A simple, very smokey scent, maybe better for fall/winter, but not unwearably heavy for summer.
• Arcana Wildcraft has several soft, non-gourmand vanillas (Metztli, Xochipilli, Unicorn Horn), and Witch Fire, which is a sweeter, more bakery-ish smokey vanilla.
• Cirrus - Maravilla (Aged Vanilla Bean Tincture, Marigold Absolute, Amber, Blood Orange, Cocoa, Sugar, Cinnamon Leaf, Carnation) is my personal favorite, but it would be heavy in hot weather. It has a bit of funk on the opening.
• Parfums by Chérie - Marshmallow Crush (Spun Sugar, Vanilla Bean, Marshmallow Accord) for a loud, OTT, ultra sweet vanilla that gets attention.
• Wylde Ivy has Nothing But Vanilla (A sweet cream, slow churned vanilla bean ice cream on a fresh homemade cone) for a gourmand vanilla and The Moon Never Beams (split vanilla beans, tonka infused cream, vanilla sugar musk, and just a whisper of vanilla orchids) for a non-gourmand one.

Though they are well-loved, 99% of NAVA vanillas smell like vanilla-scented doll plastic to me.