Dragon Age: Origins - Morrigan, Leliana, . Despite how different they were, I liked Morrigan and Leliana so much that I had a hard time deciding between them for LI.
Dragon Age: Origins: Awakening - Sigrun, Justice. I absolutely love Sigrun. She's adorable and her story is moving. And Justice was the best guy to have around righting wrongs and teaching about the world.
Dragon Age 2 - Bethany. I related a great deal the Hawke-Bethany relationship in the game because I'm close with my siblings. Fenris and Aveline were the bros that my first Hawke got along with the best over the majority of the game, but Hawke and Bethany felt like the central relationship in my story. She ended up in the Circle and it felt like reuniting with her was the most engaging part the ending for me.
Dragon Age: Inquisition - Cassandra maybe? She definitely felt like the primary best friend character for my devout Inquisitor. Aside from her Varric was kind of a cool reminder of DA 2.
Although in all fairness I find it hard to compare my feelings towards characters across multiple playthroughs with different player characters. I mean sometimes they are universally liked or disliked, but in other cases they'll may or may not become my favorites, or sometimes I'll even have drastically different perspectives.
Isabella can be a selfish cowardly former friend of Hawke or Hawke's soulmate. Zevran can be either a dead traitor or a friend.