All time - I can't answer this. Maybe when I'm on my death bed we'll see lol
Current
Pain of Salvation - The Perfect Element
maudlin of the Well - They Aren't All Beautiful
Neurosis - Locust Star
The Roots - Can't Stop This
Tool - 46 and 2
Dredg - Eighteen People Living in Harmony
Flight of the Conchords - Hiphopopotamus vs. Rhymenoceros
Jeff Buckley - Grace
Opeth - Face of Melinda
Mr Bungle - Pink Cigarette
Estradasphere - Hardball
Sleepytime Gorilla Museum - Gunday's Child
Gogol Bordello - Mishto
Testament - Fall of Siple Dome
Arcturus - Raudt og Svart
Peccatum - The Song Which No Name Carry
Devin Townsend - Earth Day
Incubus - Deep Inside
Porcupine Tree - The Creator Has a Mastertape
The Perfect Element and Face of Melinda are my best contenders for my favorite of all time, though. They've been 11/10 for me for years.