The one in flower!! The greenhouse type, Jasminum polyanthum is good, but is this partly because the scent is indoors and can'y waft away? Trachelospermum jasminoides is great too, not a Jasmine but has it in the name!!

Jasminium officinale if you want a hardy outdoor one. The variety of it called Clotted Cream is particularly good.

I agree with Fractal - we have a Jasminium officinale growing in a large tub beneath the bedroom balcony and on warm summer nights (what's 'warm?') when we have the balcony doors open, the wonderful scent wafts into the bedroom. Thoroughly recommend it!