XUbuntu take over

Hello,
I'm running xUbuntu 10.04 LTS and Ubuntu 10.04 LTS. They seem to be having a little argument. They're on seperate partitions so when I boot I get the OS selector screen. I have a choice of Ubuntu, Ubuntu recovery mode and about five others with the words Ubuntu and Linux in them. I've not tried them all, but when I select ubuntu or ubuntu recovery, it uses xUbuntu. How do I get back to Ubuntu?