In recent years, Arsenal's back four have had disastrous moments in the past; and a lot of those times it was due to center backs. Though it isn't uncommon for a defense to have momentary lapses, Arsenal's defense can't continue like this if the Gunners claim to be a world class team.
After all these disasters at the back, it is evident that the club needs defenders to patch up the defense. However, Wenger has only bought three center backs in the last year.
Laurent Koscielny, a fairly big buy, was purchased in the summer transfer window of 2010, and he turned out to be decent; sometimes solid, but mistake-prone. Another center back that he bought was Sebastien Squillaci, who was also bought last summer. Squillaci, however, turned out to be a disaster, making blunder after blunder and he isn't exactly popular among Gooners. The last purchase was Carl Jenkinson, a young Finnish center back, from Charlton; such a small buy for such a huge crisis.
I think that Wenger must buy more center backs, and here are seven whom Arsenal fans would like in their lineup.