Masch for sure, even tho some fans didn't care when he departed but you can see that liverpool without the dynamic duo of masch and alonso are very weak in the midfield. I think he still left on a good note despite not wanting to play that game vs city.
Sadly he left on a bad note, precisely because he refused to play against City - which overshadowed not only his good performance against Arsenal, but his good performances in general since joining the club from his unhappy six months at West Ham
I always took the view that him and Alonso in midfield were every bit as important as Gerrard and Torres in the 2008-09 season and we all know what happened when that partnership broke up