Here are some more ideas.
20s:
The Sheik of Araby - Inspired by the silent movie The Sheik starring Rudolph Valentino. It might be worth pointing out that, in the twenties, Arabs were considered sexy in this country.
Canal Street Blues - King Oliver’s first record. An important milestone in the history of jazz.
King Porter Stomp - Another Jelly Roll Morton composition. This one became popular again in the swing era.
Star Dust - Hoagy Carmichael’s most-recorded song. A real classic.
Happy Days Are Here Again - Written in 1929 before the stock market crash. It was the theme song of the Democratic Party for decades, until Bill Clinton replaced it with Don’t Stop in 1992.
30s:
St. James Infirmary - Best-known recording is by Cab Calloway.
Night and Day - Gotta have something by Cole Porter!
Summertime - Widely-recorded Gershwin song from Porgy and Bess. Great instrumental version by Sidney Bechet.
Sing, Sing, Sing/Christopher Columbus - Benny Goodman mixed these two compositions into one in a 1937 recording, and also in his 1938 Carnegie Hall concert. A centerpiece of the swing era.
In the Mood - Andy Razaf and Joe Garland took a riff from the Wingy Manone composition Tar Paper Stomp when they wrote this number, which became Glenn Miller’s biggest hit.
40s:
Take the “A” Train - If you use this, be sure to credit composer Billy Strayhorn.
Der Fuehrer’s Face - First featured in the Disney cartoon Donald Duck in Nutsy Land. Spike Jones had a hit with this song. While it’s not a milestone in the history of music, it’s funny and historically interesting.
I’ll Be Seeing You - This is one of the best of many homesickness songs written during World War II - a response to the war’s separation of people from their loved ones.
50s:
Rocket “88” - Claimed by some to be the first rock ‘n’ roll song.
Jambalaya - An early Hank Williams hit.
Ain’t That a Shame - Fats Domino’s first hit, and the introduction of the New Orleans piano sound to the rest of the country.
Folsom Prison Blues - Johnny Cash’s first hit.
Maybellene - Chuck Berry’s first hit.