We just got out of our interview with my wife and I think our experience will be very useful for others. It didn't go as easy as other people's and if you are married, you should read this:
Our interview times were at 8:00 and 8:30am for me and my wife respectively. We checked in and the officer found us in the waiting room after about 15 minutes of waiting (she recognized us because of the pictures in our files). We walked to her room and she opened up our binders. She was a very nice lady. She checked our passports (old and new; old one having all the visas). She asked our names, DOB, birth place, parents' names. She checked our birth certificates, both Turkish version and the translation. She checked our marriage certificate. She went through the files in our binders and asked us our last date of entries. She went through that standard list of questions like 'were you in a military, have you committed a crime, etc'. We said no to all of them. Then she asked if we have any other document proving our marriage. We didn't have anything other than IRS transcripts and bank statements (which she already had). She said she will send a request for evidence in mail. I said I have apartment lease and car insurance information but in electronic format. I asked if I can email them to her and she said sure. I emailed both documents and she printed them for us and put them in our binders. She said everything looks fine and with the additional documents our case should be approved. She said our case will be reviewed and if it requires any further documents, we will receive request for evidence but she didn't think it will be the case and we will have our cards within a few weeks. Interview took total 30 minutes or so.
Long story short: if you are applying with your spouse, bring additional documents like lease, insurance cards, bank statements, etc. to the interview. We didn't know and our case would be delayed if the officer didn't let us email them to her.
Hopefully this will be useful for other applicants.
Good luck!
Engin