Most sources note that Harold's housecarls had significantly better equipment than his fyrd, and that Williams forces were better - armoured than Harold's in general as more of them were professional soldiers or rich landowners. However, would there have been any notable differences between the equipment of the leaders and that of their elite forces? What about differences between Harold and William themselves? It's commonly recounted that William had four horses killed underneath him (however I'm not sure if this is considered truth or legend) yet obviouslt still survived, which would make one think that he was either an incredibly good fighter, incredibly well armoured, incredibly lucky, or a combination of the three.
The consensus seems to be that William would've been wearing a knee-length maille hauberk and nasal helmet, probably both of high-quality, more-or-less as depicted in the Bayeux tapestry and other contemporary representations of well-equipped fighters. If William really did have four horses killed beneath him and survived the falls, I wonder if he wouldn't have worn some form of cloth padding as well, but I definitely don't know enough about Norman battle-garb to speculate.
I've also got no idea about Harold, but my guess would be that he'd wear something similar. As far as I know, Norman and Anglo-Saxon armors weren't too dissimilar, although there does seem to have been a difference in the degree of accoutrement available to the soldiers of each army and in the proportion of professional armored soldiery, as you noted.