Let me say one thing that I'm not sure is clear.
I don't object to using the Bible to reinforce morality. It is a tool which has been used for many years to do just that, and I think it functions adequately in this regard, with one caveat:
It is never appropriate to use the Bible as evidence in moral debates. The Bible came from the set of moral tools we already possessed as humans, not the other way around. We are capable of moral behavior without the Bible or religion; people were moral before the Bible, and there are many people today who are moral without it. Besides, people that don't believe in the Bible's validity will think you are being ridiculous.
The point is that Reason should trump the Bible. We should function based on principles, not some book written thousands of years ago. If thou shalt not kill, it is because we should value life, not because we should do whatever the Bible says. Most of the people who received the most benefit from the Bible were in the past, and relatively uneducated. In this day and age, we are taught to think for ourselves. We have these big brains, why not use them?
I'm using the Bible as an example, because I am most familiar with it. The argument, however, extends to all religions. Whether or not we are going to our specific heavens or hells is irrelevant. We should be moral people regardless of whether there is a god or not.
If god tells you to kill others, then god is being immoral. How can this be? God decides what is moral. More likely, we decide what is moral. We decide when it is justifiable to kill others, not god. He may judge us eventually, but by then it will be too late.
What evidence do I have that we are moral because of each other, not god?
One, no one that I know of can talk to god. If he has changed his mind in 3000 years, then we are SOL. By the same token, if we have chosen the wrong religion, we are SOL.
Two, the language of many versions of the Bible, and of many religious texts is so archaic that it can be interpreted any way we like. Anything can be justified using the Bible, depending on what verse you choose. We already do use reason to determine what the Bible is REALLY saying, why not cut out the middleman. Realize that I am exaggerating for effect.
Three, the multitude of religions and the insistence by each that they are the sole purveyors of truth. If only one of us is right, then the rest must be wrong. How can we be sure that god's message is not lost?
There are more, but I'll leave you to think about these. As always, if I am wrong I want to hear about it!