I've got about $1,100 into the mains, $900 center and $500 surround. Then about $1,300 into the sub. I have to note that I previously kept two subs in the main system, but the addition of the SMS-1 allowed me to reduce to one sub, so to be fair, add another $600 to the subwoofer account, the value of the SMS-1 or the other sub. All in inflated Canadian dollars. U.S. residents can buy for less, much less.
In regards to the wife, it all depends on whether she cares about music or movies at all. If she loves her music, she will see the value of the system as she uses it. If she couldn't care less about music, then you have to explain that this is your hobby, it's important to you and you need to be happy even if she never turns it on once.