I'm not 100% sure on Roth IRA for married couples, but I always thought you need to have earned income to be eligible to contribute. So this might make your wife ineligible. I'm sure someone more knowledgeable than me can answer that easily.
Depending on your age and how far you are from retirement a taxable investment account can be a great bridge to your 59.5 regular withdrawal. One thing to note, its best to hold only stocks in your taxable account and preferably all of your foreign stocks due to foreign tax credits. If you choose a taxable account, you might want to switch your funds around a bit in your 401(k) & Roth/Rollover IRAs so that all your bonds are in these accounts, all your foreign in taxable, and you still meet your personal asset allocation.