Meryl Streep gleefully sang Shel Silverstein's country-western foot-stomper "I'm Checkin' Out (of the Heartbreak Hotel)" in 1990's "Postcards From the Edge" and did a lovely rendition of the old spiritual "Goodbye to Mama" a couple of years ago in "Prairie Home Companion."

So we know she can sing - and quite well.

Still, there's really no preparation for the moment early in her new movie musical "Mamma Mia!" where Streep grabs hold of the pounding beat of ABBA's "Money, Money, Money" and rides that bucking bronco of a song for its entire three-minute duration.

Streep probably won't get an Oscar nomination for singing a clutch of ABBA songs in "Mamma Mia!" unless there's a shortage of the sort of prestige turns academy voters gravitate toward.

And yet her effervescent work in this hard-to-hate musical ranks among the best in a career that has netted her 14 Academy Award nods.

Beg to differ? Try singing the showstopper power ballad "The Winner Takes It All" and get back to me.

Streep's rendition of that "big moment" song has her dramatically waving her hands a la Celine Dion while singing and speaking, whispering and bellowing the lyrics while the camera swoops around her.

Technically, it's pretty darn good. Emotionally, too.

But it's nowhere near the best of Streep's many musical moments in the movie.

Topping the list is "Dancing Queen," which starts with Streep bouncing on a bed that must have trampoline box springs and ends with her leading a conga-line procession to the coast of the movie's Greek island setting. Streep's pied-piper enthusiasm tops even Amy Adams' Central Park sing-along in last year's "Enchanted."

There's also the movie's title song, which has the overall-wearing actress writhing around on the roof, rediscovering - with a convincing degree of delight - that her libido is alive and well.

As for emotional gravitas, I'd argue for "Slipping Through My Fingers" over "Winner." Streep, whose own children have all left home now (that's why she's working more these days), sells this wistful song about a parent letting her child go:

Sleep in our eyes, her and me at

the breakfast table

Barely awake, I let precious time

go by

Then when she's gone there's that odd melancholy feeling

And a sense of guilt I can't deny

What happened to the wonderful adventures

The places I had planned for us to go (slipping through my fingers all the time)

Well, some of that we did but most we didn't

And why I just don't know

I had no idea a song like this existed in the ABBA canon. Streep imbues it with regret and sadness, but also a measure of pride in the woman her daughter has become. It's a beautiful moment.

It's another reason why her work here in "Mamma Mia!" ranks among her finest. Whether she's dancing in platform disco boots or pouring out her heart in song, Streep grounds the material's inherent silliness in recognizable and believable human emotions.

With all the awards hardware that has come her way over the years, I doubt she cares too deeply whether people recognize her for this.

Besides, who cares about awards when you get to be the dancing queen?

-- Glenn Whipp