In zone 7 you could try Moonflower Vine (Ipomoea Alba)-- huge white fragrant blooms that open in the evening. They bloom quite late in the season, but they're worth the wait.

I put in a Caryopteris ("Bluebeard") last year and was pleasantly surprised by the licorice-type scent. The scent lasted even after the blooms fell. This shrubby perennial is not fussy and, even though it is in the mint family, it is very well-behaved in my yard.

This year I am growing Mignonette and Queen Anne's Pocket Melon. The Mignonette isn't much to look at, but the scent is very strong. The "Pocket Melon" fruit is highly fragrant.

Make sure you get a species Nicotiana, the small coloured hybrids have little scent. There are strongly scented petunias, but many of those sold as scented are quite poor. Look for the species, which have quite a lax trailing habit and small white flowers, they are strongly scented. Moonflowers for something a bit different. Night-scented stock are some of the most fragrant herbaceous plants.

You might want to order (or look at the catalog) from 'The Fragrant Path'. This small seed seller has many old fashioned fragrant plants listed in its catalog.

Here is a link that might be useful: The Fragrant Path Catalog (Seeds) - Garden Watchdog

I second moonflower vine. The fragrance starts near sunset and the flowers are so luminous. Fairly mid or late summer bloomer. Loved it.

Heliotrope should definitely be on your list. It has the most amazing vanilla fragrance. 'Marine' is a lovely dark purple.

One plant that may be an aquired taste is the perennial salvia. They smell like cat pee, sometimes, but on a hot summer midday it's a very evocative scent - call me really weird! Plus, they are pretty and reliable.

Violets - you have to get down to stick your nose in them, but they are adorable anyway, and such a classic nosegay item!

If you want fragrance, go for perennials, bulbs, and shrubs. My favorites are lily of the valley, roses, lilacs, mock orange, hosta honey bells, tuberose, agastache apache sunset, dianthus superbus, viola odorata, nicotiana alata (nighttime only), snapdragons, white heliotrope, oriental lilies.

Amen to tuberose! And Night Blooming Jessamine!

Tiger eyes viola was fragrant.

Datura - "Belle Blanche" and others
Brugmansia
Heliotrope - definitely
Dianthus family - pinks, sweet william, carnations, etc.
Stocks - "regular" and evening scented
Lillies
Sweet alyssum
tuberose - definitely
Nicotiana - the "jasmine" (alata?) variety will make you swoon in the evening
Violets are very sweet but can be invasive

This year I'm trying some stuff from Select Seeds that I hope I like and is supposed to be fragrant:
Schizopetalon 'Milky Way'
Sweet Rocket
Mignonette

Thank you all so much for all of these great suggestions. I am having lots of fun looking these suggestions up. I am definitely going to get:

Nicotiana (alata), heliotrope, snapdragons, fragrant petunias, sweet allysum, tuberose and some others. Oh and definitely moonflower vine.

Maureen

Oh! Make sure Moonflower Vine is an ANNUAL in your area or plant it in a pot. I had it running rampant in my yard in P.T., WA and it was absolutely horrible! It spread by the roots and if you rototilled it... oh boy. Perhaps others can advise but I am fairly certain that's what it was. Big white flower, heart shaped leaves, etc.

I noticed tuberoses listed above. I see them in catalogs, and would love to grow them. But, I thought they were mainly a plant for the south. Do you grow them in the north? I would love to try them if they can grow in NY. How long from planting to bloom? What kind of care do they need ? Obviously, they must be dug before frost, but do we have enough frost free weather here for them? (about 4-4 1/2 months) Thanks!