There have been a number of good drafts through the years.
Edmonton's draft in 1980 may have been arguably as good as the 1979 draft with Kurri, Coffey and Moog selected. The only problem with those two drafts is they lacked quantity, unlike the Detroit draft of 1989, and several others. If you're going to pick a draft as the best overall going for quality over quantity, then it could be argued that the Habs' draft of 1971 was the best ever, with the Habs selecting Lafleur, Arnason, Murray Wilson and Larry Robinson. It could also be argued that the Penguins' draft in 1984 was the best ever, with Lemiuex and Doug Bodger. Mario makes that an amazing draft all on his own, although, I'd pick Lafleur/Robinson over Lemieux/Bodger, but not by much. Fact is none of the drafts had enough depth to be considered the best ever, particularly when some other drafts have featured both quality and quantity.
Chicago had an amazing draft in 1980 as well, arguably the best of all time:
Denis Savard (1338 points in 1196 games)
Jerome Dupont (214 NHL games)
Steve Ludzik (424 NHL games)
Troy Murray (scored 50 goals one season, 915 NHL games)
Carey Wilson (424 points in only 552 games)
Steve Larmer (1012 points in 1006 games
Jim Ralph (does a great Don Cherry; even had a cup of coffee in NHL)
Dan Frawley(273 NHL games)
Ken Solheim (135 NHL games)
Los Angeles had a helluva bonanza in 1980 as well:
Larry Murphy (second highest scoring D-man of all time)
Jim Fox (promising career cut way too short by injury)
Greg Terrion (solid checking career)
Steve Bozek (see above)
Bernie Nicholls (1209 points in 1127 games)
Daren Elliot (backup goalie)
Daryl Evans (scored famous goal in miraculous comeback playoff win over Edmonton in early 80's; a legend)
A notch below Chicago's , but one of the best ever drafts neverthelss.
St. Louis did alright in 1976, picking up Bernie Federko, Brian Sutter, Mike Liut, John Smrke, Mike Eaves and Anders Hakansson, but I would have to rank Chicago's 1980 draft slightly ahead of it due to the overall depth.
1st - Chicago 1980
2nd - Detroit 1989
3rd - St. Louis 1976
4th - Montreal 1971 (Lafleur Robinson et al)