Wee Sing has a music around the world CD that my kids loved. It features songs in their native language, then repeated in English. Ben and Leo Sidron (both jazz musicians) released a fun album some time ago called El Elefante. Some material in English, some in Spanish, some to sing along to, some to dance to, some to listen to. And as an added bonus, this is music that the adults can actually stand.
They Might Be Giants have several kids' albums, too. My gang has loved Science Is Real, which comes with a DVD of videos for the songs. (Okay, I'll 'fess up, I love it, too!) Plus they learned the difference between a meteor and a meteorite. Steer clear of this one, though, if you don't plan to teach them about evolution.
And while they aren't really sing along songs, my kids adore the Beethoven's Wig CDs. These take well-known classical music and pair it with lyrics that are instructive, silly, or both. We've had these since they were small, and my kids still walk around singing them.