Whether its a leak or not, once my video memory usage hits just over 90MB a CTD will occur.
By changing my graphic detail from 512 to 256, my initial video usage went from ~60MB to ~20MB. As a result, I didn't suffer any CTD's last night. I suspect that if I stayed on long enough to hit the magical 90MB threshold I would have CTDed. That probably would have taken a long time.
Obvioulsy, this is not a fix, but a potential work around for those experiencing problems.