Man, some of those signature songs I've never heard X.x; mostly just Hey Jude and satisfaction though. (of course I don't listen to the radio much, so songs I hear over and over are ones I *play* over and over)

Eurythmics - Sweet Dreams
AC*DC - Back in Black
Aerosmith - Don't Wanna Miss a Thing
AFI - Silver and Cold
Alice Cooper - School's Out
Aqua - Barbie Girl (;D)
Big City Groove - This Love
Blink 182 - All the Small Things
Blue Oyster Cult - Don't Fear the Reaper
Styx - Come Sail Away *or* Mr. Roboto. not sure which.
Boston - Taking My Time
Deep Purple - Smoke on the Water
CCR - Proud Mary
Cher - Believe
Coldplay - Amsterdam
Creed - Six Feet from the Edge
ELO - Blinded by the Light
David Bowie - Ziggy Stardust
DC Talk - Jesus Freak
Depeche Mode - Free Love
Dir en Grey - Child prey
the Eagles - Hotel California (but wasted time is so much prettier. . .)
Eiffel 65 - Blue
Eric Clapton - Layla. (makes me sad how Yahoo was overusing it for the longest)
Evanescence - My Immortal
Eve 6 - Inside Out
Fleetwood Mac - Don't Stop
Foreigner - Hot Blooded
Golden Earring - Twilight Zone
Goldfrappe - Train
Goo Goo Dolls - Black Balloons
Group X - Mario Twins (XD)
GusGus - Why
Heart - Baracuda
HIM - Resurrection
Hootie and the Blowfish - Time
Hooverphonic - Eden
Icon & the Black Roses - Black Rose
Iron Butterfly - In a Gadda Da Vita (sometimes I think I'm the only one that knows their other songs:/)
Jefferson Airplane - White Rabbit
Jethro Tull - Aqua Lung
Jewel - Pieces of You
Jimmy Eat World - The Middle
Kansas - Carry On My Wayward Son (Dust in the Wind is a very close second.)
Led Zepplin - Stairway to Heaven.
Linkin Park - In the End
Lionel Ritchie - Running with the Night
Lonestar - Not a Day Goes By
Lynard Skynard - Freebird
Malice Mizer - Beast of Blood
Mercy Me - I Can Only Imagine
Merry - Tokyo Telephone
Metallica - Enter Sandman
Nena - 99 Luft Ballons
NOFX - The Decline
Neil Young - After the Goldrush
Simon and Garfunkle - Mrs. Robinson
Pink Floyd - Another Brick in the Wall (pt 2 especially)
Queen - Bohemian Rapsody
Rammstein - Asche zu Asche
Rancid - Radio
Relient K - Sadie Hawkins Dance
Rod Stewart - Reason to Believe
Rolling Stones - Paint it Black
Rush - Manhattan Project
SADS - Masquerade
the Scorpions - No One Like You
Simple Plan - Perfect
Sloppy Meat Eaters - Escape
Smashing Pumpkins - Disarm
Sum 41 - Motivation
System of a Down - Chop Suey
Tatu - All the Things She Said
Ted Nugent - Cat Scratch Fever
the Alfee - Cinderella wa Nemurenai
the All-American Rejects - Swing Swing
the Black Mages - The Skies Above
the Cure - I Will Always Love You
the Postal Service - The District Sleeps Tonight
the Verve - Bittersweet Symphony
Verve Pipe - The Freshman
the Zombies - Time of the Seasonnn
They Might Be Giants - Birdhouse in Your Soul
Three Doors Down - Kryptonite
Tom Petty - Freefalling (is this because I won't let myself say refugee?)
Train - Drops of Jupiter
Weezer - Island in the Sun
X Japan - The Last Song
Zdob si Zdub - Mamaliga Malia

(two things of note-- so many of those songs *Aren't* their best songs. and so many of those bands are only noteworthy because of the one song^_^)