I thought I would post this for reference, as I had this issue and hadn't seen anyone else post about it yet. I did a new 10.0-RELEASE install awhile back, but not with x11/kde4, After setting WITH_NEW_XORG=yes in /etc/make.conf and reinstalling x11/xorg for x11/kde4 I found that my USB mouse would not work, but my PS/2 keyboard would. Just for the heck of it, I tried building x11/xorg without HAL and with DEVD, and that took care of the issue. After rebooting (and removing hald_enable=YES from /etc/rc.conf), my usb mouse was working fine. Hopefully this helps out anyone else who needs to upgrade their X.Org to install KDE, only to find their USB mouse not working.