Well, you said "ultimate turn-on outfit for a woman to wear on a date", so I guess I can be a specific as I want...
Lunch:
Pale blue painted-on jeans with a white, fluffy sparkly top that falls off one shoulder to reveal a bra strap. NB. Don't wear a strapless bra - the whole point is that you're flashing your underwear a little. Make sure it's a beautiful bra, even if only the strap is visible. Enough make-up to show some effort and creativity without plastering it on. Bubblegum pink lips and nails and matching stiletto pumps. Keep jewellery to a minimum but make sure what is there is stunning.
Dinner and/or evening drinks:
Swap the jeans and top for a short, soft, stretchy, sparkly bodycon dress - something that shows off your figure but won't be uncomfortable after a meal.
Doing stuff:
If it's warm and we're doing stuff as opposed to sitting in a restaurant or a bar then a cheeky looking sundress, fitted around the waist with a playful, short A-line bottom half... or maybe a short, pale blue denim skirt with a hot pink strappy vest. I love legs, arms and shoulders so it's more about how much of you I can see than the actual clothes.
If you're going to be on your feet a fair bit then swap the pumps for trainers but, crucially, trainers which coordinate with your outfit/make-up and are of a light, feminine looking design, not those gormless, plain white, hoofy looking things that seem to be the default setting for most women these days.
Whatever the time of day:
"Pleasures" by Estée Lauder. Seriously - I'd hit on a wheelie bin of it were wearing that stuff! Keep a small bottle in your bag and apply liberally mid-date if you like me and want to make sure I'm hooked!
One other thing:
For me it's all about the details. Creative and interesting (but not excessive) use of make-up, beautiful nails, fabulous shoes, minimal (while exquisite) jewellery & accessories and gorgeous fragrance. Get those right and you could wear a bin bag and I'd still find you irresistible!