Alrighty! We've just got some juicy new info from the gameplay demo, in particular some info on the skill list. Time again to speculate!

COMBAT
One-Handed (confirmed to include dual-wielding, so that cannot be a seperate skill)
Two-Handed
Block
Heavy Armor (confirmed)
Smithing
? (Hand-to-Hand, perhaps?)

MAGIC
Destruction
Alteration
Restoration
Illusion
Conjuration
Enchanting

STEALTH
Marksman
Light Armor (implied from Heavy Armor being a seperate skill)
Sneak
Speechcraft
Alchemy
? (Security, maybe?)