We are chugging across the Navajo Indian Reservation along the northern edge of Arizona in my best friend Kerrie's 1973 orange Super Beetle, high beams blazing on the long, black highway. Miles pass in an endless loop of one broken white line after another. We are two hours outside Flagstaff -- 90 minutes if we floor the little engine and press to get there before dawn.

In the January chill, the car heater is whirring. The only sound louder than a VW heater on this night are our voices -- big and badly vibrato -- keeping up with every lyric on a cassette of "Blue" by Joni Mitchell, who is playing smoky piano and singing "The Last Time I Saw Richard."

Nothing ever softened the hard edges of a road trip from Salt Lake City to Northern Arizona University like a stack of Joni Mitchell tapes. We attended college there in the late '70s.

Before that, we survived our years at suburban Olympus High School, battling the popular girls and boys who wouldn't look at us twice by moping around and immersing ourselves in Joni. Committing every lyric, every guitar riff to memory, we fancied ourselves just like her, eking our way through puberty as confessional kind of girls. We wore a lot of dark colors, read a lot of Sylvia Plath's poetry. Looking back on it now, we must have been a little scary.

I thought of all of this in the process of justifying a little post-Christmas splurge -- the purchase of Mitchell's latest CD, a two-disc compilation called "Travelogue." I bought one for myself and one for Kerrie.

Mitchell, Canada's best-ever musical export, is a tough-to-fathom 59 years old now. She vowed upon releasing the CD late last year that it would be her final recording. She says she is giving up on the music business, describing the industry as "calculated for sales, sonically calculated, rudely calculated."

"I'm ashamed," she said in a Rolling Stone interview last year, "to be part of the music business. I just think it's a cesspool."

She has floated this "I'm ending it" balloon through much of her career, and who can say whether she means it. It doesn't matter. Critics have chided her for coasting through "Travelogue" -- a hits collection with full orchestral backup. They delight in pointing out that Mitchell's voice sounds closer to 60 than 30. True enough. But to her fans, this voice is still complex. It flies and floats, and each song is still a poem.

Mitchell could go quietly, retire tomorrow. She hardly needs more accolades. Like so many other accomplished women well past middle age, she needs no one's approval. Mitchell already did the part of sexy and cerebral gypsy in the '60s and '70s. Did it awfully well.

She continues her 25-year association with jazz greats Herbie Hancock and Wayne Shorter and keyboardist Billy Preston, men she has collaborated with on several albums. She could do worse than devote the rest of her days to her other love -- painting.

Scores of young music fans hardly realize that Mitchell's long and lovely fingers are all over much of today's pop and folk-inspired creations.

Tori Amos and Prince have covered "A Case of You." Jazz vocalist Cassandra Wilson has recorded "Black Crow," and Janet Jackson has covered "Big Yellow Taxi." You can hear Mitchell in Michelle Branch and Vanessa Carlton.

And it's hardly just moony girl stuff. Those boy singers are cashing in on her, too. Close your eyes and you can almost hear Mitchell's pained narratives of crushed relationships and arrogant lovers in the musical pinings of Ben Folds or of Dashboard Confessional, with singer Chris Carraba doing work every bit as dark and dreamy as Joni's ever was.

Joni reinvented. Nice.