I'm not really a huge fan of protest songs, but I'd nominate:

Public Enemy - "Fight the Power"
!!! = "Me and Giuliani Down By the Schoolyard"
"La Marseillaise"

I'm not sure it's quite a protest song, but "Brother Can You Spare a Dime?" by Bing Crosby hits me hard every time.

so VH1 recently did a top 25 protest songs show -

25 (What's So Funny 'Bout) Peace, Love and Understanding - Elvis Costello
24 Rockin' in the Free World - Neil Young
23 Where Is the Love? - Black Eyed Peas
22 Do They Know It's Christmas (Feed The World)
21 Nelson Mandela - The Specials
20 London Calling - The Clash
19 Fortunate Son - Creedence Clearwater Revival
18 Boom! - System of a Down
17 People Have the Power - Patti Smith
16 The Message - Grandmaster Flash
15 Biko - Peter Gabriel
14 Freedom [Live] - Rage Against the Machine
13 Sun City
12 Anarchy in the U.K. - The Sex Pistols
11 Get up, Stand Up - Bob Marley
10 Born in the U.S.A.- Bruce Springsteen
9 Fight the Power - Public Enemy
8 Sunday Bloody Sunday - U2
7 Ohio - Crosby, Stills, Nash & Young
6 Strange Fruit [#2] - Billie Holiday
5 What's Going On - Marvin Gaye
4 Give Peace a Chance - John Lennon
3 Say It Loud (I'm Black and I'm Proud), Pt. 1 - James Brown
2 This Land Is Your Land - Woody Guthrie
1 Blowin' in the Wind [Live] - Bob Dylan

Born in the U.S.A.- Bruce Springsteen

I had that one in mind last night, and then forgot it.

Surely if you're gonna have one Costello, it's Shipbuilding. If 2, Shipbuilding and Tramp the Dirt Down. If 3, actually, Oliver's Army, Shipbuilding and Tramp the Dirt down.

And I will post, first class, one English pound to anyone who can convincingly explain what Anarchy in the UK is protesting about.

Costello didn't even write it. It's a cover of Nick Lowe.

Good point.

Boom! - System of a Down

Nice! I think they have better "protest songs," though, considering that one's mostly spoken word. "A.D.D." and "War?" come to mind. But I think "Boom!" is more reactionary, and the video is very protest-y.

is more reactionary

I'm not sure that word means what you think it means

I've always loved (in a crank-up-the-volume-and-scream-the-lyrics / get-into-the-mosh-pit-when-they-play-it-live kind of way) "Youth Against Fascism (Hate Song)" by Sonic Youth:

another can of worms
another stomach turns
yeh yr ghetto burns
it's the song I hate, it's the song I hate

you got a stupid man
you got a Ku Klux Klan
yr fuckin' battle plan
it's the song I hate, it's the song I hate

a sieg heil-in' squirt
you're an impotent jerk
yeh a fascist twerp
it's the song I hate, it's the song I hate

black robe and swill
I believe Anita Hill
judge will rot in hell
it's the song I hate, it's the song I hate

yeah a cross on fire
by a christian liar
a black attack on fire
it's the song I hate, it's the song I hate

yeah the president sucks
he's a war pig fuck
his shit is out of luck
it's the song I hate, it's the song I hate

another nazi attack
a skinhead is cracked
my blood is black
it's the song I hate, it's the song I hate

we're banging pots and pans
to make you understand
we gonna bury you man
it's the song I hate, it's the song I hate

I'm a human wreck
a redneck in check
I killed the teacher's pet
it's the song I hate, it's the song I hate
it's the song I hate, it's the song I hate
it's the song I hate, it's the song I hate
it's the song I hate, it's the song I hate
it's the song I hate, it's the song I hate
it's the song I hate, it's the song I hate

Also seconding the "Ignoreland" love....