@jakeblues - you're not alone in having this problem, there was an issue raised on github about a month ago - see https://github.com/raspberrypi/linux/issues/29
- it's been reported by numerous people now but it doesn't seem like anything is being done about it.
I've tried both Squeeze and Wheezy - they both behave the same, fine until LXDE is started then I lose my network connection and the mouse and keyboard work only sporadically if at all.
The last apt-get upgrade and rpi-update I did has made things worse - previously I could sometimes get out of LXDE and check log files as the keyboard would start working again, but now I just get a black screen on logging out of LXDE and I have to power off the RPi to reboot.
To look for error messages after startx, if you have a network connection to your RPi you may be able to login from another machine using ssh - which I believe is enabled by default in Wheezy but can be enabled in Squeeze too. You'll probably see constant errors in dmesg from the moment X starts.