I'm just going to go with my top 4 runs from some of my favorite bands, it's much too hard to pick just one...
Led Zeppelin
I
II
III
IV
Creedence Clearwater Revival
Bayou Country
Green River
Willy and the Poor Boys
Cosmo's Factory
Black Sabbath
Black Sabbath
Paranoid
Master of Reality
Vol 4
Rolling Stones
Beggars Banquet
Let it Bleed
Sticky Fingers
Exile on Main St.
Queen
Sheer Heart Attack
A Night at the Opera
A Day at the Races
News of the World
The Beatles
Revolver
Sgt Peppers
The Beatles
Abbey Road
The Doors
The Doors
Strange Days
Waiting for the Sun
Soft Parade
Pink Floyd
Dark Side of the Moon
Wish You Were Here
Animals
The Wall
Rush
Rush
Caress of Steel
Fly by Night
2112
AC/DC
High Voltage
Dirty Deeds
Let There be Rock
Highway to Hell
The Who
The Who Sell Out
Tommy
Who's Next
Quadrophenia
Cream [Honestly one of the only bands with a "perfect" discography... Zeppelin, Creedence, Eagles, and the Doors have one too if you don't count all of their last releases.]
Fresh Cream
Disraeli Gears
Wheels of Fire
Goodbye
Simon & Garfunkel
Sounds of Silence
Parsley, Sage, Rosemary and Thyme
Bookends
Bridge Over Troubled Water
Some metal bands had some seriously epic runs too worth mentioning:
(Slayer's 4 album run is definitely my favorite 4 album run out of any band [though tied with Sabbath], especially in terms of progression, dynamics, growth, and style. The only two runs that could honestly top this one for me is if I could alter the orders and have Zeppelin I, II, III, and Houses of the Holy or Meddle, Dark Side of the Moon, Animals, and the Wall.)
Slayer
Hell Awaits
Reign in Blood
South of Heaven
Seasons in the Abyss
Megadeth
Peace Sells... but Who's Buying?
So Far, So Good... So What!
Rust in Peace
Countdown to Extinction
Metallica
Kill 'em All
Ride the Lightning
Master of Puppets
And Justice for All
Iron Maiden
Iron Maiden
Killers
The Number of the Beast
Piece of Mind
Powerslave [yeah, no way in hell I was going to exclude the debut or Powerslave... Easily the best first 5 albums in a row by any band, only rivaled by Creedence, Zeppelin, Sabbath, Rush & The Doors]