Played them all, abeit some of the early ones was brief. my favourites were, morrowind (although i recall it being very sandy brown alot of the time) and Skyrim. Oblivion was good and i did enjoy it, but my early memories have to be daggerfall. i think its such a long time ago. early to mid 90's i think.
With each passing generation of the franchise, the game just got better and better. worlds got more interesting. the lore became richer. the history found in the books i recall my memories and remember the days when i was much younger playing and wasting hours in a single player game. but well worth the ride.