Before I get into it though I should mention that I started reading Iron Man at issue #198. The first three artists on those first three books were Sal Buscema, Herb Trimpe and Mark Bright! I am not sure how you can get off to a better start than that.
Anyway... here goes nothing.
Tom Morgan (Issues #307-319)
Tom did a run toward the end of the first series. Issue 319 was an issue where I believe he said "It's going downhill from here. Better get off the ship. He did stories that involved the Mandarin, War Machine, Titanium Man, Crimson Dynamo, Cap, and Black Widow. Very solid artwork, especially considering the armor he had to work with. My book met him once and is grateful for it!
10) Kevin Hopgood (issues 280-288, 290-297, 299-306)
Kevin transitioned Iron Man through War Machine to the armor that was used in the television show. Both are difficult to draw without making them look crappy. It was a good run with a lot of great covers. Very solid.
9) Don Heck (Tales of Suspense 46-62, 64-72)
Don Heck was one of the original Iron Man artists and although the style is simple I adore the classic looks and this was a period where they were being innovative (for the time) and subtle changes were being made(look at the rivets in the mask)..
8) Gene Colan (issues 1, 253, Annual 10, 13, 15 Tales of Suspense issues 39, 73-99, Iron Man/SubMariner #1)
A legend. Classic style that was very consistent. Lots of longevity as well. I love the cover to issue #1.
7) George Tuska (issues 5-13, 15-24, 32, 38, 40-46, 48-54, 57-61, 63-72, 78-79, 86-92, 96-106, Annual 4)
I met George Tuska at a show back in the 90's(and embarrassed myself greatly in the process) and since then I have really grown to appreciate his work on Iron Man. He created the looks of many characters over his run and although later in his life I feel all of his artwork looked the same, I have great respect for the groundbreaking artist who were consistent and were able to do it without computers or other modern technology.
I am surprised that Paul Ryan ended up this low on my list since I LOVE his work so much. Most of the work he did was during the period with the bubble arms and legs Iron Man and everyone that had draw it made it look more cartoonish and less clean than I generally like. If he would have done more work in other periods he would be higher on the list. Still, I love Paul Ryan's work!
5) Herb Trimpe (issues 39, 82-85, 93-94, 113, 199, 246, 251-252, 255)
Herb Trimpe penciled the second issue of Iron Man that I ever purchased and although his work on Iron Man is not terribly extensive I have a soft spot in my heart for his work because of it. Once again, a master of consistency and polish. What is not to like?
4) Luke McDonnell (issues 163-195, Annual 7)
Luke McDonnell does an excellent job of the essence of Iron Man and even when Rhodey takes over he is able to portray Rhodey's personality in the armor's look. He had longevity and was the artist through some of the most classic of stories. He also drew my favorite issue, Assistant editor's month Iron Man #178. A great run and very consistent.
3) Bob Layton (issues 91, 116-128, 130-135, 137-153, 215-244, 246-250, 254, 256, vol. 3 issues 2, 25, Bad Blood 1-4, Legacy of Doom 1-4)
Bob Layton is an absolute legend as far as Iron Man is concerned and would probably be higher on the list if he wasn't such an arrogant douche bag. He also did a lot of covers and inked many issues but did not draw as many as you would think. I have not had any luck getting what I want from him over the years although what he gave me has been excellent. His artwork is clean and consistent and he designed several versions of the armor over the yearsv(although he won't draw at least one of them but I'm not bitter about it).
2) John Romita jr (issues 115-117, 119-121, 123-128, 141-150, 152-156, 256, 258-266)
I absolutely love John Romita jr's work and he is a really cool guy. I met him at a Motor City Con in the late 90's. He was walking up the aisle, slid across the table, sat down and started drawing. After he was done with my sketch he looked up at me and said my sketch was the easiest sketch he had ever done! It had taken him about a minute to do! Great style during a time when they were making lots of changes to the armor. He also draws a great drunk Tony!! (!Issue 128 is the Demon in a Bottle issue)
1) Mark Bright (issues 200-201, 203-208, 210, 215-217, 220-223, 225-231, 274, Annual 9, 15)
I absolutely love Mark Bright's take on Iron Man. From the Silver Centurion, which if not drawn with conviction looks like a crappy transformer, to the return of the traditional look, his work was always solid and worthy of a second and third look. He had longevity and did the pencils throughout the Armor Wars story. Anyone who can draw armors and make them always look great is amazing in my book.
I absolutely adore the cover to 215.
Well that is what I have come up with. It is like choosing which of your children you like the best. Thank you for your time.