That´s sooo hard! I love so many of the dollhouse characters! Can I make a top 10 list?
HM:
Mellie/November - Mallie is just so cute! And how such a cute, sweet and kind person can be such a badass, is awesome!
#10
Daniel Perrin - Alexis Denisof!!! Just seeing him again with Eliza (so many Wesley and Faith feels!) and him being on a show again with Amy (Fred/Wes feels overload!!!)
#9
Mag - Felicia Day!!! playing a lesbian redhead! All I could ever ask for! (other than Alyson of course)
#8
Adele DeWitt - She is so powerful and badass. But so human and vulnerable at the same time. How she cares for Topher in epitaphs is so cute!!! And I like her accent.
#7
Sierra - Victor/Sierra is the purest and sweetest relationship on the whole show! They´re so cute!!! Sierra is amazing!
#6
Echo - Eliza Dushku!!! She is badass, cute, smart, beautiful and so much more!
#5
Alpha - Alan Tudyk!!! I love how Alpha is so crazy. He has so funny moments. My favourites are the medicine carrots, the quotes: "I´m not fooling. He´s not kidding. We´re not bluffing. I´m bluffing. But the rest of us, we mean business.", "I spoke to the schizophrenic in me. Well, both of them actually." and my favourite is when someone tells him to watch his step and he does...

That just cracks me up everytime!
#4
Victor - He is such a sweetie! Enver Gjokaj is a really great actor (at least from what I´ve seen in dollhouse)! Victor/Sierra is so cute! And I love it when Topher is imprinted in him and like he really
is Topher, he really behaves exactly like him, so funny! And Victor as Kiki is so funny too!
#3
Bennett Halverson - Summer Glau!!!! Her awkward kiss with Topher was so cute and funny! Really liked her story, so sad Whiskey killed her

#2
Claire Saunders/Whiskey - Amy Acker!!!! Just love Amy so much!!!!! Love Whiskey! And Dr. Claire Saunders really cares for the actives/dolls. And I ship Claire/Topher

😍 💗 (I´m reading and writing fanfics about them)
#1
Topher Brink - OMG! Love him sooo much! And Fran Kranz!!! Topher is so cute and naive and I don´t care what people say about him being amoral, I just loooove him! It was so sad how his story ended, OMG I cried like a baby when he died!!! But he died as a hero. And just all his scenes in the epitaph episodes mostly, I just always want to hug him. The epitaphs break my Topher-Loving-Heart. 😭 And the best part about him is just how funny he is!!!!!

To me his funny-ness is one of the best parts of the show.

😂 🤣 🤣
But as others already said, no matter how amazing and awesome the characters are and how much I love them all... The story is the star.