Other than the NT Event log, what are some good tools I can use to monitor
various items like failed logon attempts and general Network Admin stuff.
Another tool I need is one that will go through all of our user accounts and
show me the last time they were logged into.

Up until recently, we haven't had good standard practices in place and
finally feel it's time. Accounts were created on a whim and never tracked,
so I assume we have dozen's of stale accounts.