D'Addario EJ45 Pro Arte NT Classical Guitar Strings, Full Set
[EJ45]

I have used this string forever, as have about half of touring professionals (like David Russel). These strings have tremendous sound and perfect intonation. Trebles are perfect, not too bright, not too mellow. Basses are solid. Tension is lighter than most any other brand, so they are easy on both nails and left hand fingertips. If you have a new guitar, this should be the string you try first (or J46 which is just as good, just a little higher tension).