Rose by far. Martha, Donna, and Clara are all still very good, but Rose is my personal favorite.
that's hard, at first i didn't like rose, but now i love her, i couldn't stand martha (she was so clingy and annoying as hell), donna was fricken awesome and i loved her, amy and rory together was perfect, and i liked clara but i've never liked her as a companion or her relationship with the doctor (they didn't really click well)
so it is a tie between:
rose
donna
amy and rory (as a pair, not by themselves)
but if i had to pick it would probably rose because her and ten together was perfect
Amy Pond
Rose :)
Martha. I liked her spunk..
