I'm told that head-butting in soccer is a lot more damaging than it looks, and can in fact lead to serious problems over time. And while I wouldn't call soccer a contact sport in the same way that football or hockey is - where contact is a basic fact of every play, at all times - I would say that I've seen some soccer players eat shit in spectacular ways, and some of those legbreaks are nothing to laugh about. Also, no padding or equipment to speak of.
That said, trying to compare the athleticism of these sports is kind of hopeless. The soccer guys are balanced athletes. The balance is cardio vs. strength, with a heavy emphasis on cardio. Soccer players might go for 45 minutes at a time, with almost no breaks, hockey players are on the ice for a minute or two, with frequent breaks. This is why hockey players make soccer players look like utter pansies, in terms of physique - they need explosive power, they need tremendous strength, but their cardio isn't nearly as important. Two or three minutes of hard playing, break for awhile.
In terms of fighting, athleticism has almost nothing at all to do with how a street brawl turns out, and the rules would be a deciding factor. My guess is that over 10 rounds, an equal weight soccer player would take out an equal weight hockey player. But if we're talking about the streets? The soccer player would be unconscious within literally seconds, and that's just the fact of the matter.