Finally got around to reading Amazing Spider-man #s 688 & 689 last week and was taken aback by how Peter Parker was drawn in 688 (he doesn’t appear in 689). I mean, he looked so little like what I imagine Peter Parker to look like, that until he was identified by name on the next page I thought we might be looking at Flash Thompson!
This drove me to go back through my collection of Amazing Spider-man issues to see how Peter had been depicted over the years and I ended up putting together a collection of panels showing our hero in his civilian appearance over time.
While doing this work showed me that there were quite a number of times where was some shoddy penciling or inking work that made him not look like himself (esp. in the late 90s and early 00s), generally speaking there is some form of continuity across the decades. All the Peter Parkers may not look the exactly same depending on who is drawing him and when, but you can always tell who it is supposed to be at first glance. (Click on the image below for a larger version).
For the record, though, to me the definitive Peter Parker is by John Romita, Sr.
As for the source of these panels, the first one is Amazing Fantasy #15, after that they are all from ASM #3, 39, 39, 82, 118, 154, 189, 226, 263, 299, 335, 371, 410, 446, 481, 529, 565, 601, 640.