Popular '80s rock music, like all music, is subjective; everyone will have their own opinions about what is good or bad, the best way of discovering which is the most popular would be to check a number of different lists posted by random people and find the songs/artists they have in common. For example, the lists posted on http://www.sndcntrdj.com/songlist/80slist.htm and http://mag.weddingcentral.com.au/music/songs/top1080s.htm both list A-Ha's "Take on Me" and the Bangles' "Walk Like an Egyptian" as two songs that belong in the popular '80s rock music genre. Though most would agree, there are still many list posted that do not include those two.
I would say that the best way of finding out what you wish to know would be to search for lists derived from the actual music charts of the '80s; the music charts show popularity based on how many fans bought the music and how many requests for certain songs were called into the radio stations (some even include poll information), these would give you the most accurate picture of what was considered popular back in the day.
In this writer's opinion, I love all the music that came out of the eighties (except for some of the really slow ballads). It is what I grew up listening to and, considering the dramatic turn that today's music has taken, I believe that it is all a lot better than what you can hear on the radio today. Before Beyonce there was Madonna, before The Black Eyed Peas there was ZZ Top. Songs had more substance and feeling back in the '80s then the music played now, now it seems to be nothing but pandering to the masses and trying to come up with the next big thing (i.e. Justin Bieber) than writing something real. I do understand that this isn't entirely the artist's fault, they have demands to meet, and most (after all the pandering) do gone on to write something original, but because society doesn't recognize it as cool they get shuffled to the back and are never heard from again (see The Veronicas).
When popular songs from the '80s, like "Footloose" & "Love Shack), are compared with popular songs of today, like "Poker Face" & "The Real Slim Shady", I think their superiority stands out. Not to mention that the music back then was music that the whole family could listen to, while to day every other song is filled with gross obscenity and horrible stereotypes. I don't know about everyone else, but I am tired of hearing songs that encourage children to fight, men to treat women like crap, and songs telling women that the only way to get a man is by being promiscuous. Granted, there are plenty of songs from the '80s that do the same thing, but at least they came up with a far more creative way of saying it.
All that aside, when it comes to the music of the '80s, you're gonna like what you like and whether or not it's popular shouldn't influence you. For a list of music that I personally love beyond a doubt (and hopefully you will too), check out this list: http://www.afn.org/~afn30091/80songs.html.