For me, Kos. Thought he had the groan factor in spades last season. This season he has been fantastic. If he and Verm stay fit we have a security that has been missing for a few seasons now.
Koscielny for sure deserves a special mention, proving to be exceptional. Also Sir Chez. I think we all knew he could be good, but he's been exceptional. I think with a first choice back 4, we have the makings of a very good defensive unit. Roll on August !!!
My other choice was for Arteta, a surprise that he can play as he does for us.
Koscielny has to be up there he was written off by everyone despite good appearances against barca last year this season he has been exceptional for true arsenal fans probably expected him to come good but a lot of people where questioning him