Can I take out a car loan and register the car in my spouse's name?

A financed car has to be registered in the primary borrower’s name. The only way that you could be on the loan and not on the registration is if you were to cosign for your spouse. If the vehicle is going to be a gift, unfortunately there is no way to not ruin the surprise, though with a gift this big it’s probably better to include your spouse in the decision-making process anyway.