Yup, I know what you mean.
I hate wasting food and often save
leftovers to make someting else
as it was hot hot - personally i'd cook
it.
When you cook it you take it to such a
high temp as to kill off the bacteria,
that have started breeding, whereas if you
leave it over night they could make you
sick.
When you defrost anything and aren't going
to cook it you need to keep the temp below
5-6c, if you do cook it then it isn't such
a problem.
That's what I learned as a chef.
I mean it's up to you, but for me
personally - i'd cook it now to be safe.