My perfect daylily has large ruffled, fragrant, diamond dusted, clear colored flowers with good substance that always open early and well, proportionately displayed on tall, well branched and budded scapes, on a plant which has beautiful blue-green rust (and other disease) resistant foliage (rock solid resistance), which also reblooms.
(Since dark colors generally don't do well in my climate, I'd add (except that it is too hard to put all into one sentence!) that the blooms would generally be light colored (near-white, yellows of various sorts, golds, oranges, pinks, peaches, lavenders, polychromes, etc.) that also sport a narrow colored edge, metallic edges being preferred. Eyes are optional. UFs, doubles, and polymerous daylilies are welcome. The amount of ruffling desired depends on the form of the flower, but in no case should cause opening problems in the flower.)