I thought this would be a good thing to try out and see how it goes. For starters, each couple starts out with 20 points. For the couple you like, +5 points and for the couple you dislike, -5 points. Here are the couples:

Derek and Meredith 45
Mark and Addison 20
Finn and Meredith 15
Derek and Addison 15
Derek and Rose 15
Mark and Lexie 15
Mark and Teddy 20
Owen and Cristina 20
Owen and Teddy 20
George and Callie 20
George and Meredith 20
Alex and Addison 20
Alex and Rebecca 15
Alex and Olivia 20
Alex and Izzie 20
Jackson and Cristina 20
Burke and Cristina 20
Marlow and Cristina 20
Arizona and Callie 20
Erica and Callie 20
Mark and Callie 20
Richard and Adele 20
Richard and Ellis 20
If there is a couple I forgot to add, feel free to add them to your list.