I am about to invest in a pair of new roller skates and have been researching helmets. Thousand Heritage seems to be the best for Dome Shaped Helmets, but be prepared to drop a pretty penny (worth it to keep your nogan safe!)
It's a strange thing to recommend because ideally you buy one of these things and never need it. So I'm grateful to say that I've not yet tested my helmet's integrity! But I have a Bern helmet and it fits well, and I like the look!