Mr. Ramsey's insight on managing money is very wise, in my opinion. His views regarding the nature of money and wealth is a bit more difficult to navigate.

Dealing with your specific questions:

Is having valuables and excess money a sin?

No to the first, and so long as that money is not gained illegally or unethically, no to the second. We do not actually "own" the money, anyway; we're merely caretakers for it. It all belongs to God, and as long as how you use that money reflects that truth, then I do not see a problem.

Is saving for retirement sinful?

In and of itself, no. Saving for retirement allows you to not be a burden to your children in your old age; it allows you to leave an inheritance to your children and grandchildren, which Proverbs encourages. Plus, saving wisely will allow you to give at a level that would be impossible otherwise; you can give so much more if you're sitting on a $6 million account than if you only have a few hundred thousand dollars to your name.

Is my tithe well spent?

You would need to talk to your church leaders about this issue. Get involved; I'm sure they would love for someone to take an interest in what the church is doing. If not, try to affect that change.

Do Churches need these million dollar facilities?

Probably not, but again, you'd need tot talk to your church about this.

Does Jesus think my tithe is sufficient?

Sufficient for what? Remember that it all belongs to Him, anyway. Jesus calls us to give up everything; we are to use it to further the kingdom. For some, that means selling all and giving to the poor. For others, it means saving and investing so that thousands and millions can be given later.

Wealth is not evil; wanting wealth is evil.

For what it's worth, I share your concerns. For this reason, I will not be buying any video games for a long time; I cannot justify that increasingly large expense in the face the dozens I already have and enjoy while that money could be going to more productive places. My wife and I have also decided that for Christmas, we will not be buying our family members gifts (which they don't really need anyway), and will be donating that money in their names to charities and services for the very needy around the planet.

You are right in not wanting money to control you; it's a very easy trap to fall into. That does not mean we have to fear money. We have to control it for the glory of God, so that we may serve in ways we could never imagine otherwise. Money is a powerful - and dangerous - tool.