I thought my experience may provide a bit information to some of you.
I am a F1 married to USC in Feb. 2006. Before becoming F1, I was under H1B1. I have been in the US for more than 6 years.
DO: Houston, TX
Received date: 4/2/06
Notice date: 4/6/06
Finger print: 4/28/06
Interview notice: 5/1/06
Interview date: 6/22/06 --approved and got stamped on the passport
I was very surprised that the whole process only took them less than 3 months. I filed I-131 and I-765 with I-485 and I-130 at the same time, but never heard anything about my I-131 and I-765. I guess they were expecting to give me GC shortly, so they didn't even bother to process my I-131 and I-765.
My husband and I took a lot of documents with us and prepared questions they may ask the night before. However, during the interview, we were only asked questions like "what is your name", "what is your address", "what is your birthday", "do you have any children", "have you been married before". I was asked "when was the last time you entered US" and my husband was asked "have you sponsed any other people to the US before". Basically, she just compared our answers to the application we sumitted. The officer did not ask us anything about "us". Not even how we met.
Besides my passport and my previous visa document, the officer also asked for things we had together and documented them. We only had health insurance, checking and saving account together. I am my husband's IRA account beneficiary. She was pretty ok with it i guess, since she didn't say any words, but just wrote them down.
We consulted a lawyer in Houston before we submitted the application and she told us that the fastest processing time she experienced recently was 4 months. It usually takes 6 to 12 months. Maybe I was just lucky. However, my husband and I are the same race, similar age (late 20s), have not been married before, and both have professional degrees and stable income. I don't know if those are also reasons that our processing time and interview time are so short.
BTW, I highly recommend consulting a decent lawyer before submitting the application. Ask the lawyer everything you are not certain regarding the application. We paid $100 for one hour consultation and the lawyer also allow us to e-mail her for any additional questions. The lawyer helped us to fill everything right on the application and submitted all required documents to the right place. Actually she also told us to attach photocopies of bank accounts, bills, photos we had together with the application. She told us that immigration officers processes many applications everyday, so you want your application stands out and make them have no doubt that the marriage is real.
Good luck to everyone of you who are still waiting for the GC.