Blue: S/T (1973)
Blue's eponymous 1973 debut, by far the band's best album, is low-key Beatlesque pop that slots in as a quieter cousin of Badfinger and (to a lesser extent) Big Star. Gentle guitar hooks and soaring harmonies place them into that group of proto-power-pop purveyors who never really got their due (though you can hear some strains of Blue in the later indie pop of fellow Scots Teenage Fanclub).
The album opens up with the solid one-two-three punch of "Red Light Song," a lovely, harmonic ballad that's pure seventies sunshine, followed by the more rocking "Look Around" and the great lost Badfinger ballad "Someone." That any of these failed to be a minor classic rock hit at the time is somewhat bewildering.
The balance of the album bounces between mid-tempo pop and quieter ballads, with the occasional power pop rocker like "Little Jody"; maybe not a lot of truly memorable tracks, but it's rarely less than enjoyable (though some tunes, like the Calypso-tinged "Skye Banana Boat Song," haven't aged as well as others).
Alas, later albums are less infectious; the 1974 follow-up, Life In The Navy, wasn't bad, just a bit more bland, while successive releases (some produced by Elton John) descended into mostly faceless adult-oriented balladry. Still, the debut is worth hunting down (though the existence of other, more popular acts with the same name can make it confusing).
Here's a video for "Red Light Song":