My best guess would be Stock (Matthiola incana). I find the fragrance of stock is similar to Dutch Hyacinths. And both are exceptionally wafty.

They're very cheap too and only cost $2~3 for a six-pack at my local nurseries. They prefer the cooler seasons and when Summer comes, they usually bow down.

Here is a link that might be useful: Stock info

How about some old-fashioned petunias? ;)

Here is a link that might be useful: Old-fashioned petunias

I want fragrant annuals this year, too.

I'm going to be trying to Stock and Alyssum.

if you have something for them to climb on, moonflower vine is evening-fragrant. you could also try heliotrope, flowering tobacco and sweet peas.