Bukkit uses 100% of my CPU (Build #733)

Hello !
I'm running a Bukkit server on a dedicated server with Mineshafter. But, since I updated my server to build #733, the Java process have took 100% of my CPU, and once a I'm connected on it, it lags.

Configuration :
CPU : Intel Xeon 2.33 GHz
OS : Windows Server 2008 R2 Entreprise x64
Java : Version 1.6.0_24

Launcher :

Code:

"PATH TO JAVA, I DON'T WANT TO REWRITE IT" -Xmx700M -Xms700M -jar Mineshafter-server.jar craftbukkit.jar

The server was running nicely before I updated. What's wrong now ?
I've like 10 plugins working on the server. Can they have an impact ?

Can someone help me ?

Thanks !

EDIT : I tried to launch Bukkit without plugins and the problem disappeared. I'll list a list of all plugins installed.