I have a nice ssh-key system setup for connecting to KVM hosts, and through permission settings on:

/var/run/libvirt/libvirt-sock
/var/run/libvirt/libvirt-sock-ro

I managed access to the guests. Recently upgrading to intrepid brought along a new version of virt-manager, that whenever you add a QEMU+SSH libvirt instance in, it forcibly adds ‘root@’ to the URI where before the username was left out. If you add a URI like ‘bryanm@host’ it becomes ‘root@bryanm@host’.

Use gconf-editor, under apps -> virt-manager -> connections add new URI’s by hand rather than using the virt-manager interface as a workaround.

edit: launchpad bug #294965, Red Hat bug #470416.