If you submit an original valid passport (or a notarized or certified copy of a valid passport), you do not need to submit any other documents. Otherwise, you must submit at least two of the documents listed below. The documents must be current*, verify your identity (that is, contain your name).... and there is a list of supporting documents that you can send such as drivers license, birth certificate, voter id, etc...
Last time I came back, I took my wife's birth certificate with me as I needed that for DS-230 and then I also told my wife to mail me the voter id because losing a voter id in mail is better than losing a passport. I took both original to my bank and got them notarized and sent them with my W7 on March 5th with my return and today I already got her ITIN number in the mail (in just 2 weeks) . Now just waiting to see a big fat deposit in my bank account and filing return jointly would also help during her interview at the embassy.
Edited by hindustani24, 21 March 2011 - 09:00 PM.