Series: Invincible Iron Man (1968-2004)

Stan Lee and (mostly) Don Heck.  Grade: C+.  Tales of Suspense #39-72 (1963-1965
Stan Lee and (mostly) Gene Colan.  Grade: C.  Tales of Suspense #73-98 (1965-1968)
Archie Goodwin and (mostly) Johnny Craig or Don Heck.  Grade: C-.  Iron Man #1-28 (1968-1970)
Gerry Conway and Don Heck/George Tuska.  Grade: D.  #35- (1971)
Mike Friedrich and (mostly) George Tuska.  Grade: C-.  #48-55, 58-59, 61-69, 71-75, 77-81 (1972-1975)
Bill Mantlo and George Tuska #86-87, 95-115 (1976-1978)
David Michelinie and John Romita Jr. and/or Bob Layton.  Grade: A+.  #116-153 (with some fill-in issues) (1978-1981)
Denny O’Neil and Luke McConnell (note: Denny started scripting with #154).  Grade: A.  #161-195 (1982-1985)
Denny O’Neil and (mostly) Mark Bright.  Grade: B.  #196-208 (1985-1986)
David Michelinie and Bob Layton.  Grade: B. #215-250  (1987-1989)

This series took a pause in 1997 for the (awful) heroes reborn period, followed by a Busiek “#1” reboot that eventually folded its numbering back into the original “Invincible Iron Man” series.