Fallout 3 is my all time favorite game, and in my opinion one of the pioneers in One Player Roleplay. It combines deep development and content with a format that literally opens up a world for you to explore at your own pace. Skyrim was a great game, but in all reality, the map was designed to make it linear, which to me defeats the purpose of "open world". When Vault 101 opened, sure the door pointed toward Megaton, but all sides were open and you could take any path you chose; as opposed to Skyrim, where the only legit "IC" choice is to follow an NPC to the nearest town, then be sent up a road to the next. I think it was less entertaining because it limits the adventure, unless you disobey the game and stray from the clearly over-beaten path.

Also, the writing of Fallout 3 was amazing. The most unimportant characters had their own stories and consistent personalities, where as in Skyrim, the only characters with any individuality are directly quest related.

Let me know what you think.