Pink Floyd-Dark Side of the Moon
Alice in Chains-Dirt
Jimi Hendrix-Are You Experienced?
The Beatles-The White Album
Nine Inch Nails-The Downward Spiral
The Grateful Dead-Fallout from the Phil Zone
Be aware that the majority of mainstream music that is often considered to be stoner music usually sucks and is played out like a motherfucker.
For example, Pink Floyd's Dark Side of the Moon should be substituted with Electric Wizard's Dopethrone, regardless of personal taste.