Neutral:
* Storyteller
* Narrator
* Chronicler
* Relator
* Recounter
Negative:
* Gossip
* Rumormonger
* Scandalmonger
* Liar (if the tales are untrue)
* Boaster (if the tales are exaggerated)
* Braggart (if the tales are about their own accomplishments)
Positive:
* Bard (if they tell traditional stories or epics)
* Griot (if they are from a West African tradition of storytelling)
* Minstrel (if they use music to tell stories)
* Chronicler (if they record historical events)
The best term to use will depend on the specific situation and the tone you want to convey.