Neo classic would be my favorite as it was the first armor when I started reading comics. But plenty more since then, too many to name actually.
Honestly, there’s usually something to like about every Iron Man Armor for me. The ones that stick out the most to me are MK.50 (IW), MK.42 (IM3), Marvel Now, classic red and gold armor, and any armor with silver/gray mixed in.
His third suit. The first one with the red and gold color scheme. This one is slightly before my time, but back around 1976 or so, the older kid living next door had a pvc figure of this Iron Man armor, and without having any idea who the character was, it fascinated me. Years later, when I went back looking for old issues featuring this version of the suit, I was surprised to find out it had only lasted a few months. Like in Avengers, it suddenly shows up in issue #3 where the Avengers are hunting Hulk and Namor, in issue #4 when they find frozen Cap, but then by issue #6, he's already moved on to the next Iron Man armor. In Iron Man's own book, Tales of Suspense, it lasted a little longer... #48-53. But still, a very short time.
Probably the (comic) Hypervelocity armor. Not really for the design but rather the concept of Tony's mind being copied into the armor and the end product having to adjust to, from his perspective, transhumanism.
Yeah, that was the suit I grew up with. And even though he'd had a few different Iron Man armors before that one, it was shocking to me when they gave him a new one after that. He'd had that one for many years longer than any of the others up until then, and I always thought that was his final form. Also, I hated they got rid of the gold. I dropped the comic when he got the Silver Centurion armor lol
