Are solo efforts ever better?

A couple of these might be arguable depending on your tastes and preferences.

Joe Walsh

Donald Fagen

Bjork

Natalie Merchant

Janis Joplin

Billy Idol

Ice Cube

Ronnie James Dio

Sammy Hagar

St. Vincent

Joan Jett

Moby

Tom Petty

If you start digging into jazz, it would be easy to come up with a list 2 or 3 times longer.

I'm with lowrider57 when it comes to Debbie Harry and Eric Clapton. I saw Deborah Harry and Blondie at the Santa Monica Civic. They were just plain fun. I still listen to a couple of their albums.

As for Clapton, thanks to his work with the Blues Breakers and Cream, he remains my favorite electric guitarist. He's the reason I bought an electric guitar. I got to say, though, that when I saw him in concert he was a bit of a snooze.

Why should not two heads (or more) be better than one?

Todd Rundgren > The Nazz.

Michael Jackson > The Jacksons

Bjork > The Sugarcubes.

Neil Young > Buffalo Springfield.

Brian Eno > Roxy Music

I would push back and vouch for Sting's solo career. The Police were The Police and no one can ever take their genius and influence away from them, but Sting has managed to carve out a memorable and influential solo career more successful and deep than his Police days. Then again, he also has grown up, too.