You need to see your estate planning attorney. Unless you transmuted title to community property, the property remains your separate property. If your wife dies first, your basis stays the same. If the property were transmuted to community property the value would step up to fair market value regardless of the order of death.
Note, the property is separate. If you were to get divorced, you keep it. If you transmute the property, your wife is entitled to half (this is a bit of a summary, there are some complexities that are not necessary to get into).
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I agree with the prior attorney but want to add that if you wish to transfer the property to you as husband and wife in order to get the step up upon the death of the first spouse to die, make sure you use the words that you are hereby "transmuting" your separate property into community property and hereby hold it as Husband and Wife as Community Property with right of Survivorship. This gets a complete step up at the time of either party's death. Don't hold it as Husband and Wife as Joint Tenants as you will only get a step up on the deceased spouse's interest rather than a double step up in basis.
There is both a tax-planning opportunity and an estate planning opportunity here. I strongly recommend you look on Avvo.Com under Find-A-Lawyer and seek counsel from an Estate Planning attorney ASAP.