Fragrance and taste abilities are an individual matter. Much has been studied and written about the subject. The best answer to this question asked by an individual requires a trip to the annual spring Lilac Festival in Highland Park, Rochester, NY. where every lilac variety is planted. One is free to wander, touch and smell each blossom. A delightful experience. Worth the trip.

I don't think the fragrance of the common lilac - the ones remembered from many childhoods - can be beaten. My neighbor and I have a continuous hedge of them planted 4' apart at the turn of the last century. So, between our two properties, we've got an old city block lined with them and they're show stoppers in bloom. Fragrance is intoxicating.

We're just coming off one of the harshest winters in history; things are a bit behind schedule, but catching up fast. This will be a heavy bloom year for lilacs if mine are good indicators.

That sounds great Duluthinbloom. Would love to be your neighbor! :-)

Another place to sample different lilac fragrances is at the Arnold Arboretum in Boston. They have a 'Lilac Day' when they are all in bloom. It usually is around Mother's Day, but not sure about this year.

I had some purple lilacs that I didn't enjoy because the blooms were not very dense and the shrub itself had mildew on it most of the season. But it did have good fragrance. I pulled those out thinking I could replace them with a better variety and on impulse bought a white lilac called 'Avalanche' that had these huge blooms on it. It has not had great fragrance or been very vigorous, since I bought it. And the large blooms droop. So that would be one I would avoid. And those blooms have been fully open for a week and are starting to deteriorate already. I'm still looking for another purple lilac with great fragrance too. I like that 'Beauty of Moscow' and may look for that one.

You could also visit nurseries about now and sample the scents. As Nandina says, scent is quite personal, and so you really need to judge for yourself.

I am late to the conversation, and agree with the overall sentiment of some of the comments (individual variability in olfactory systems). However, I can absolutely say that for me, I am not a fan of the scent of some syringa persicas or syringa pubescens subsp. patulas. Though I will always grow them for their vigor and beauty in the garden, I find they have this strong "spring flower" scent that just isn't for me (some daffodils have this distinct scent). I find this very different from other lilacs I grow, like Beauty of Moscow and Blue Skies.