If you're interested at all in that Whitburn Project, or even if you're not, you should take a look at this tag cloud, highlighting the most frequently used words in Top Forty hit song titles. (It claims to go back to 1890, but I think that has to be a typo. Otherwise "ragtime" and "band" and "Alexander's" would be in there.)
"Love" is the biggest and boldest word there, which comes as no surprise, since love is all you need. I do think it's odd that "blue" is roughly in second place. I wouldn't have expected that. Maybe they counted Michael Johnson's "Bluer Than Blue" twice.
It's getting late here, but I wonder how many song titles contain only those 100 most popular words? "Believe" and "Beautiful" and "Kiss," of course, but also "Wonderful World," "Oh Girl," "Heart Light," "Forever Young," "Ain't Nobody," and probably a few hundred more.