I never liked Christina when she's with any man. I liked her more when she was either having non-committed sex or just as herself like she was at the Mayo or where ever she was. Sometimes it really bothers me that it's a rare female character on TV that isn't pining after some guy and I guess I just really like that part of Christina.
I really am not an Owen person. I was when he started on the show to a point. And I even enjoyed her relationship with him on/off but the more serious it got the less I liked it. And I think part of it is that that relationship was blooming in the midst of one disaster after another.
Arizona I didn't mind until she hooked up with Callie. At this point I feel like they bring the worst out in each other. Callie gets ultra needy and Arizona gets ultra selfish.
About the only character I seem to enjoy these days is Karev. Sometimes I feel like he has the most depth out of all of them.