I just happened to be scrolling through Marvel's website, and it looks like they're streaming the X-Men and Spider-Man cartoons from the '90s. I think these are probably my two favorite adaptations of Marvel. In terms of comic books overall, Justice League murders all. And while X-Men tends to be gratingly melodramatic ("Scott!!") and Spider-Man ended on a cliff-hanger (Where was the real Mary Jane) both were pretty good considering the time.
Save your eyes. Take breaks.