Greg Maddux, who is about to announce his retirement from baseball, is a cinch for election to the Hall of Fame: 355 wins, .610 winning average, ERA+ of 132. But Maddux, like recently-retired Mike Mussina, shouldn't be ranked with the "immortals" -- the 16 Hall of Fame pitchers whose excellence, in my view, ranks them above their peers. (See this post and this post for relevant background.)
Maddux had only two 20-win seasons, which is why he isn't an "immortal" pitcher, in my book. Roger Clemens, Maddux's contemporary, had six 20-win seasons (in addition to his 354 wins, .658 winning average, ERA+ of 143), which would make him an "immortal" but for the strong suspicion that his career totals were inflated by steroids and HGH. (It is, by the way, a strong suspicion that cannot be confirmed by statistical evidence.)
P.S. (12/08/08) The election of Joe Gordon to the Hall of Fame is a joke, by my reckoning.