Maybe not really prog, but who cares. Nick Drake was a fantastic (acoustic) guitarist and vocalist who released three records early in the seventies before dying of an overdose of antidepressives(!). Bryter Layter is his most bright record, however, and the one of his records with the most complex arrangements. The atmosphere of this record is typically similar to the eating-breakfast-on-a-Sunday-in-a-house-in-the-forest-with-the-sun-coming-in-through-the-window atmosphere (maybe I'll reconsider that when I've got into the lyrics). As the base is always Drake's ingenious guitar playing and very pleasant, non-intrusive voice, but on this record there are also some bass playing and very tasty string arrangements. The ten folk songs (not being medieval in any way) could be too simple for many prog fans, but what the #¤%(=£ - one needs to listen to some lighter music sometimes (Magma and Henry Cow twenty times every day isn't good for your stomach in the long run), and this is as good as it comes. If this record is to be compared to anything, I'd pick the more laid-back stuff by the Basque band Itoiz and the Canadians Harmonium. There is some excellent flute playing on two tracks, and most notably on the last track, "Sunday", which contains some of the nicest flute playing in the history of music. The track "Poor Boy" (including piano, saxophone and female vocals) sounds inspired by soul (and jazz), but is nice anyway, for some mysterious reason. An excellent record, but not for the same reasons that most other records on this site are excellent. If you want pure prog, then stay away.
Rather similar to Bryter Layter, but significantly more melancholic. The arrangements and compositions are generally a slight bit more interesting and varied on Bryter Layter, but which of the records you'll prefer will depend on what mood you're in. My recommendation is that you first get Bryter Layter, and if you like it, get this one too. [Drake's last record, Pink Moon, contains only Drake's vocals and his guitar, so I'll not review it here. It is, however, maybe impossible to make a better record when using only voice and guitar].
