... according to about.com
1. The Beatles
Essential Album: Revolver
With record sales estimated at more than a billion worldwide, no other band had a greater influence on the course of rock music.
2. Pink Floyd
Essential Album: Wish You Were Here
They had one of the flashiest stage shows of any band, but their music gained its most fame being used in movies.
3. The Who
Essential Album: Who's Next
One of the first, most successful, and longest lasting "power trios," this group was innovative both musically and technically.
4. Rolling Stones
Essential Album: Sticky Fingers
The original "bad boys" of rock, they are among the most durable bands, recording and touring with few breaks since they began in 1961.
5. Led Zeppelin
Essential Album: Led Zeppelin IV
Their Stairway To Heaven is believed to have received more radio airplay than any other song in history, even though it was never released as a single.
Essential Album: Their Greatest Hits
Another of rock's longest-lasting acts, their 1976 greatest hits album is the biggest selling album of all time.
7. Grateful Dead
Essential Album: Anthem Of The Sun
One of San Francisco's first "flower power" bands, their fan following is nearly as strong today as it was when the group disbanded in 1995.
8. Jefferson Airplane / Jefferson Starship
Essential Album: While Bathing At Baxter's
Pioneers of the Psychedelic Rock genre, they were in the vanguard of the counter-culture of the '60s and '70s.
9. The Doors
Essential Album: The Doors
In spite of a short life and limited discography, they became one of rock's most popular and influential groups.
10. Moody Blues
Essential Album: Days Of Future Passed
With the exception of a few years in the mid-70s, this progressive/psychedelic group has toured and recorded since 1964.
11. Fleetwood Mac
Essential Album: Rumours
After numerous personnel and musical style changes, their 1977 Rumours album is still among the top ten best selling albums ever.
Essential Album: Back In Black
This pioneering hard rock/heavy metal group has sold an estimated 100-million albums worldwide.
Essential Album: Boston
When their first album was released in 1976, it was the highest grossing debut album ever seen up until that time.
Essential Album: Wheels Of Fire
The group existed for less than three years but staked its place as one of the first and most enduringly popular of rock's "power trios."
15. Def Leppard
Essential Album: Hysteria
Futuristic instrumentation and vocal harmonies have kept them near the top of the all-time best selling album lists for a quarter of a century.
16. The Byrds
Essential Album: The Byrds' Greatest Hits
Aomng the pioneers of Folk Rock, their popularity in the mid-60s rivaled that of the Beatles.
Essential Album: Toys In The Attic
Originally written off as Rolling Stones imitators, the group has consistently produced multi-million-selling albums for 30+ years.
Essential Album: Abraxas
This groundbreaking Latin Rock group timed the release of its first album to coincide with a highly successful performance at Woodstock in 1969.
19. Blood Sweat & Tears
Essential Album: Blood Sweat & Tears
Virtually a small orchestra, this group established a milestone in rock history with its large horn section and jazz-blues orientation.
20. Van Halen
Essential Album: 1984
One of the most innovative and influential heavy metal groups of the late '70s, the group continues to perform some 30+ years after its inception.
21. ZZ Top
Essential Album: The Best Of ZZ Top
The self-proclaimed "little ol' band from Texas" was one of the earliest influences in Southern Rock, and continues so, three decades later.
Essential Album: The Joshua Tree
Ireland's best known rockers have been a successful fixture on album charts and in concert venues since their formation in 1976.
23. Allman Brothers
Essential Album: Eat A Peach
The success of their unique fusion of hard rock, blues, jazz, and classical music has secured this group's immortality.
Essential Album: Greatest Hits
Its jazz-flavored progressive rock sound has been a fixture in the rock scene since 1973.
Essential Album: John Barleycorn Must Die
This group had far greater success with albums than with singles, and thrived in spite of numerous personnel changes and long breaks.
Here's my top ten.
1. The Marshall Tucker Band
2. Jethro Tull
3. Bob Dylan
4. Pink Floyd
5. The Outlaws
6. The Charlie Daniels Band
7. The Ozark Mountain Daredevils
8. Crosby, Stills, & Nash
9. Buffalo Springfield