Marvel's Strongest Heroes
This image shows Marvel's first real attempt to categorize it's heroes according to their strength levels. This was printed in the back of "Amazing Spider-Man Annual" # 15, 1981, which pre-dated (and helped inspire the "Official Handbook of the Marvel Universe" less than two years later. It seems quite inaccurate now, but back then it was pretty close. Most thought the Silver Surfer and Colossus ranked to low, but each ended up with his strength defined at a higher level when the OHOTMU came out in '83.
As of today, marvel has made many versions/updates of the Handbook, but the debates still rage; Who's stronger? Who's the better fighter? Who's more powerful? Etc. Though the editorial staff set out to give us fans answers to these questions, their subsequent inconsistencies have merely fueled the fire. Still, this was a fun chart and the Handbooks have been informative and pretty good overall (imo) as well. I thought putting it atop my list of Marvel's strongest heroes would be appropriate.
I've listed the some of the weight (in Tons) that some of these guys were stated to be able to lift.
MU = Official Handbook of the Marvel Universe. The number after the apostrophe is the year that edition started being printed. The number after the colon is the Weight the character was stated to be able to lift in Tons.
If some of these characters don't have info for every edition (or any info at all), I'm still getting to it or the info hasn't yet been decided officially by Marvel.