'Safest' filesystem defaults

[mal content]

Hello.

Which filesystem options are the 'safest' in terms of data loss
after power failure?

I'm current using:

/dev/ad0s1f on /usr (ufs, local, soft-updates)
/dev/ad0s1d on /var (ufs, local, nosuid, soft-updates)
/dev/ad1s1d on /mnt/home (ufs, local, nosuid, soft-updates)
/dev/ad0s1e.eli on /tmp (ufs, local, noexec, nosuid, nosymfollow)

We currently have a serious problem with power outages, so I'd
like to make sure that my filesystems don't get damaged by power
failure until I can install a decent UPS system.

thanks,
MC