Musical Acts You Have Seen both as headliner and as opening act
 

I'm including only acts that have toured on a national/international scale, but if others want to include local or regional acts, knock yourselves out.

Pixies: opened for Love And Rockets

Roger McGuinn: opened for The Band (classic lineup)

Johnny Dowd: opened for Pere Ubu

The Dickies: opened for TSOL--Black Flag was the official headliner but I didn't stay to see the current Black Flag tribute band that Greg Ginn is touring with

Karla Bonoff: opened for Jackson Browne

Todd Rundgren: opened for Daryl Hall & John Oates

Sierra Hull: opened for Uncle Earl

John Fogerty: opened for Willie Nelson

Scrawl: opened for Great Plains, and for Wussy

Great Plains: opened for Nick Cave & The Bad Seeds, and for Half Japanese

Webb Wilder: opened for Jim Lauderdale

Riders In The Sky: opened for Mark Willis

VOLK: opened for The Electric Six

I've seen indie pop extraordinaire katie dey both headlining a show with an industrial artist and opening for a screamo concert. It's an interesting combo, to be sure.

Breeders opened for Nirvana
Magik Markers opened for Sonic Youth
Boris openend for Amenra