Depending on what is meant by "greatest." If it's greatest to me, that's one thing. If it's for a record mag, I can imagine people would start listing things like Led Zeppelin, Def Leppard, The Doors, the Beatles, etc.
Anyway, most meaningful and greatest for me: (some of these actually suck now or don't exist, so I refer mainly to their earlier work)
1) Nine Inch Nails - now a cliche and popular, back in 1992 they were unheard of and I listened to their songs many a night while I burned myself with cigarettes and smoked weed. Just kidding.
2) Depeche Mode - multiple good albums, some crap, most good. New album only one good song, Wrong, but still.
3) My Life with the Thrill Kill Kult - spectacular mix of industrial, goth, sleaze-disco
4) The Orb - many college days spent listening to them while playing road rash on Sega Genesis and smoking weed. Kidding again, I never used illicit drugs that anyone can prove.
5) Old Gangster Rap - aka, NWA, Geto Boys, Ice Cube, Too Short, 2 Live Crew - I listen to that stuff now and for the most part it's terrible, but was definitely the "greatest" as far as my development was concerned.
Honorable mentions include Nirvana, which I hated in 1992 but now like, Ministry, old albums kick ass, Lords of Acid, KMFDM, Skinny Puppy, Pigface, Primus