First post has a lot of good recommendations from the 20s that I stand by. I'd rewrite most of the second post, though. I'll just do an overview here of what I'm familiar with:
30s -- swing/big band, western swing, acoustic/country/delta blues
40s -- western swing (cont), electric blues, honky-tonk, bop, vocal groups (less familiar)
First post has a lot of good recommendations from the 20s that I stand by. I'd rewrite most of the second post, though. I'll just do an overview here of what I'm familiar with:
30s -- swing/big band, western swing, acoustic/country/delta blues
40s -- western swing (cont), electric blues, honky-tonk, bop, vocal groups (less familiar)
50s -- bluegrass, rockabilly/rock & roll, honky-tonk (cont), folk revival, post-bop
60s and onward is a lot harder to follow, but...
60s -- folk, folk-rock, psych rock, psych folk, PLUS all sorts of jazz (bossa nova, modal) and country (Bakersfield Sound)
70s (note country drops off the map here) -- jazz-fusion, free jazz, disco, soul, singer-songwriter (less familiar), prog (less familiar)
80s -- post-disco, smooth jazz (yes, it can actually be good), punk, detroit techno, proto-house, rap (less familiar), new wave (less familiar)
90s -- house and beyond (my knowledge outside of dance music drops off pretty hard after the mid 80s)