I have seen:
Linkin Park (3 times)
Bush
Foo Fighters
Neon Trees
A Day to Remember
Foster the People
Young the Giant
Bad Religion
Cage the Elephant
The Strokes
Lol not many for my years but awesome all the same,Linkin Park,Coldplay and The Prodigy.
I have seen so many bands! I was only 8yrs old when I went to the one music festival first time. After that I have seen many many bands!
But I never forget those five times when I saw Linkin Park 
@Provinssirock 2008
@Sonisphere 2009
@The O2 Arena 2010 x 2 (+LPU Summit)
@Kaisaniemi (+meet&greet)
Linkin Park (8x)
Rise Against
Rammstein (2x)
Slipknot
Limp Bizkit (2x)
Beatsteaks (3x)
System of a Down
Red Hot Chili Peppers
Foo Fighters
My Chemical Romance
Sum41 (2x)
Papa Roach (2x)
Placebo
30 Seconds to Mars (2x)
Good Charlotte
Avenged Sevenfold
3 Doors Down
Disturbed
Skillet
Enter Shikari
Billy Talent
Alter Bridge
Guano Apes
Middle Class Rut
Anberlin
Stone Temple Pilots
Dredg (2x)
Faithless
Funeral for a Friend
Coheed & Cambria
Disco Ensemble
Madsen
Halestorm
Carpark North
We are Scientists
Jack Johnson
Deichkind
The Futureheads
Selig
Jupiter Jones
Sacrety
Jimmy Eat World
The Black Pacific
Riverboat Gamblers
Verea
Julien-K
The Hives
Egotronic
Crookers
Buckcherry
Coliseum
Deathstars (2x)
Kraftklub
Livingston
Prime Circle
Fall of Death
Yashin
Linkin Park (x3), 30 STM, All Time Low, Jimmy Eat World, Robyn, Deadmau5. In other words; not so many. I saw all of them at the same festival actually… 
But I’ve seen a lot of Norwegian bands, tho
Unfortunately i’ve never been to any live shows :(( LOL i was always looking after my neice so my sister could go to see avenged sevenfold and stone sour.
i know what my first will be, Linkin Park it will be epic to be in the crowd.
can’t wait for them to come back to uk, so i can go!!
hopefully now that im a member here i can get a change for meet n greet.
Well… hope i remember them all…
In my younger days:
Bomfunk MCs
Postgirobygget
Turbonegro
since 2009
Metallica x2 Bergen & Oslo
AC/DC
Sonic Syndicate
H-Blockx
Kiss
Rage Against The Machine
Cypress Hill
30 Seconds To Mars x 2
Airbourne
Dizzee Rascal
Muse
Rammstein
We Are The Fallen
Bullet For My Valentine
Five Finger Death Punch
Jay-Z
Pendulum
Rise Against
Slash
Slayer
Alice In Chains
Cancer Bats
Project 54
Volbeat
As I Lay Dying
Lamb Of God
Stone Sour x 2
Coldplay
Kings Of Leon
Millencolin
Social Distortion
Avenged Sevenfold
The Gaslight Anthem
Beatsteaks
System of a Down
Bring Me The Horizon
Disturbed x 2
In Flames
Korn
Hollywood Undead
Rob Zombie
Sevendust
Wolfmother
…And You Will Know Us By The Trail Of Dead
Asking Alexandria
Black Stone Cherry
All That Remains
August Burns Red
Architects x2
Jimmy Eat World
Papa Roach
Halestorm
Down
Buckcherry
Linkin Park
Wow! Some of you guys have seen so many bands live (& multiple times)
I have seen My Chemical Romance, Paramore, & Smashing Pumpkins. I have yet to see LP live.
The Cars (actually, that was my first concert ever), Tears for Fears, Janet Jackson, and TobyMac. Sadly, I have not seen Linkin Park live yet 
I went and saw alter bridge and steel panther last night in enmore Sydney. Was a fun show
I have seen quite a few.
Linkin park, Foo Fighters, Smashing Pumpkins, Rage Against the Machine, Bjork, Grinspoon, LCD Soundsystem, Dizzee Rascal, Enter Shikari, The Nightwatchman, Arctic Monkeys, The Living End, Sneaky Soundsystem, The prodigy, Bullet for my Valentine, Pendulum, Birds of Tokyo, Lupe Fiasco, Serj Tankian, The naked and famous, Muse, Lily Allen, Groove Armada, Girl talk, Rise Against, Mastodon, Calvin Harris, Karnivol, The temper Trap, Tool, Rammstein, M.I.A, Deftones, Die Antwoord, Ratatat, kids of 88, Shihad, Crystal Castles, Soundgarden, Noel Gallagher’s high flying birds, My Chemical Romance, Cavalera Conspiracy, parkway drive, Royksopp, Cage the Elephant, Foster the people, Best Coast, Das racist, Yellow card, Alien Ant Farm, Blindspott.
I may be missing some.
I saw: Linkin Park (x6), Julien-K, blink-182, Anna Lohr, Rainer Von Vielen, 30 Seconds To Mars, The Blackout, The Used, Green Day, Rise Against, Guano Apes, N.E.R.D., Sick Of It All, Billy Talent, Sum41, and a lot more 
I saw Skillet, Red, and The Letter Black a couple years ago, but that’s about it for me. XD
Well that’s a lot if I count the festivals…
concerts: Linkin park (x2), Dead By Sunrise, Deftones
Upcoming: Skrillex
Festivals:
LL11: Crystal Fighters, Crystal Castles, de Staat, Aphex Twin, Chase & Status, Skrillex, Boef en de Gelogeerde aap, AKS, Within Temptation, the Roots and many more.
Upcoming Festivals:
LL12: I know skrillex will be coming… but the line up isn’t published yet
PP12: Linkin Park, Kyteman, Chase & Status, Racoon, Soundgarden and many more!
linkin park
green day
30 seconds to mars
boyslikegirls
the maine
there for tomorrow
silverstein
while she sleeps
the blackout
lostprophets
mayday parade
escape the fate
we are the ocean
every avenue
cobra starship
all time low
deaf havana
story of the year
silmple plan
blood red shoes
all american rejects
good charlotte
jimmy eat world
his statue falls
and some dutch bands… and I’m probably forgetting some
Hmmm… only Linkin Park. Had the chance to attend Green Day’s concert, but I didn’t
Rammstein, 30 seconds to mars (3x), The pretty reckless
Just Panic! at the Disco & 30 Seconds to Mars u.u
try to remember all bands and how often I saw them…
Linkin Park (3x)
30 Seconds to Mars (2x)
Lovex (1x)
Lauri Ylönen (1x)
The Pusher (2x)
Jim Kroft (2x)
Culcha Candela (1x)
Revolverheld (2)
Sunrise Avenue (more than 8x)
Jennifer Rostock (1x)
Reamon (1x)
Livingston (1x)
Billy Talent (1x)
Blink 182 (1x at their first Germany gig after reunion)
David Garrett (1x, listen from behind the stage -.-)
Bandgeek Mafia (2x)
Green frog feet (1x)
Panik (4x)
I am sure that I forgot some of the bands…
Let’s see…
I’ve seen
Linkin Park
Ozzy Osbourne
Incubus
Foo Fighters
Rise Against
Styx
38 Special
REO Speedwagon
Red Hot Chili Peppers
and last but not least, The 7 Shot Screamers