For non-critical Linux systems, I often move things /tmp and /var/log to tmpfs to save on some disk writing. I've been doing this for a year or so and if I ever need the logs across reboots, I just comment out a line in /etc/fstab and then start debugging.

In any case, I would like to do the same thing on OS X. I've seen posts on creating a ramdisk for OS X, but I'm looking for a more permanent solution. I always want /tmp and /var/log mounted in a ramdisk, with the ability to turn that off with a bit of cmdline editing in vi if I have to.