Here's #47! Click here for the master list!
Once again, there is a really good argument to be made that an issue of Kirby and Lee's Fantastic Four should be this pick, as well, as #47 continued the Inhumans storyline (and I believe #47 was the first appearance of the Inhuman's black sheep, Maximus the Mad).
The Inhumans storyline, besides introducing some notable Marvel characters, was a great epic storyline, with a lot of bombastic Kirby action and character design (what design work he did in this story!) plus a nice humanistic hook for the story to rest on (Johnny/Crystal).
However, I was considering perhaps going with the first appearance of Scott Lang, the second Ant-Man, in Marvel Premiere #47.
Then I remembered Batman #47, which I think is a truly memorable issue, as this is the issue where Batman's origin is first told in full - all under a really nice Bob Kane (of whoever was his ghost in 1948) cover.
The Bill Finger story has become etched in our memories, and this is where it was really laid out, including the whole "Joe Chill" part of the story.
I think this is definitely a top choice for this number.
The usual suspects show up with notable #47s - Gaiman, Moore, Morrison, Ellis (on Stormwatch), Milligan (on Shade) and Lee/Romita.
Any other big ones that I didn't mention?
Reader Ajit reminded me that Dian Belmont first showed up in Adventure Comics #47, that one I should have remembered, but I totally thought that Dane Whitman (Black Knight) debuted in Avengers #48, but nope, after checking the issue, Dr. Whitman was in the previous issue (he just didn't become the Black Knight until #48)!