Hard Day's Night.

You're Pushin' Too Hard from The Seeds

Breakin' Up Is Hard To Do from Neil Sedaka

Hard, Ain't It Hard

Hard Travelin'

Hard Knock Life

from Annie

and from Jay Z

Too many dance tracks to mention...

Blondie has a track "The Hardest Part" and the Jesus and Mary Chain have "The Hardest Walk" as well as "It's So Hard"

Lots of songs with "Easy" in them, too, I bet.

Falling In Love Is Hard On The Knees -- Aerosmith

It's Hard To Be A Saint In The City -- Bruce Springsteen

She Works Hard For The Money -- Donna Summer

Hard Times by Johnny Cash, It's A Hard Life by Queen, and Mick Jagger's Hard Woman.

Searching through my iTunes, excluding almost all the ones mentioned above:

Hard Time Killing Floor Blues—Chris Thomas King (O Brother Where Art Thou soundtrack)
Hard Hearted Woman — Cat Stevens
Hard To Concentrate — Red Hot Chili Peppers
Hard To Explain — Cowboy Junkies
Harden My Heart — Quarterflash (agh, K-TEL 80s compilation)
Harder On You — The Knack
I Ain't Hard To Find — Paul Wall (Entourage soundtrack compilation)
Hit So Hard — Hole
Party Hard — Beenie Man
Sorry Seems To Be The Hardest Word — Elton John, also Ray Charles
Try Too Hard — Pink
Can't Hardly Stand It — Charlie Feathers

Hard Makin' Money - The Joys
Hard On - Withered Hand
Living This Life Makes it Hard - The Dutchess & The Duke
Fall Hard - Shout Out Louds
Harder Better Faster Stronger - Daft Punk
Don't Give Me a Hard Time - The Locarnos
No Matter How Hard You Try - Young Galaxy
So Hard - Dixie Chicks
Hardwood Pews - Horse Feathers
Harder to Breathe - Dear Abbeys
Hardrock Hallelujah - Lordi
Get It On the Long Hard Road - Kleptones
Hard Time - Chris Thomas King
Hard Fucking - Tenacious D
Hardest Part - Coldplay
Harder to Breathe - Maroon 5
Hardest Button to Button - White Stripes
Hardcore UFOs - Guided by Voices
The Hard Way - Faith Hill
Hard on the Ticker - Tim McGraw
Hard Day's Night - Beatles
Coming Even Harder - Lords of Acid

Hard to Handle - The Black Crowes
The Hardest Part - Blondie
Why do you have to be so hard to love? - Bryan Adams
Cold Hard Bitch - JET
It's So Hard - John Lennon
These Hard Times - Matchbox 20
Hardly Gettin' Over It - Husker Du

Lots of songs with "Easy" in them, too, I bet.

How about "Easy To Be Hard"?

Hard Times In New York Town

Too many blues songs to mention, too...

Hardhearted Hannah (the vamp of Savannah)