Skyrim *might* make my top 10 in terms of hours played, but isn't in the list as a favorite. There are too many nostalgic faves that can never be topped.
1) Adventure - Atari 2600
2) Legacy of the Ancients - C64
3) Bard's Tale I & II - C64
You're listing Bard's Tale 1 (excellent) and other C64 games, but not Archon or MULE? How dare you! (I actually thought of Daggerfall as the perfect/improved successor to Bard's Tale.) I'd also add some others in as well, such as Zork 1 - 3 and Summer & Winter Games.
Also, both Bandit Kings of Ancient China and Civ 1 caused physical injuries to several athletic college students. If obsession leading to injury (from sitting in a chair for > 24 hours) is a measure of greatness, either of these would be at the top.
But I'd rate Skyrim pretty high, definitely top 10, maybe top 5--hard to say when you're mixing genres.