See Tables 1, 2. and 3 on pages 2, 3, and 4 of Publication 501:
http://www.irs.gov/pub/irs-pdf/p501.pdf
No. Same-sex marriage is not legally recognized in Louisiana. A same-sex married couple living in Louisiana must file separately as "single" on their state income tax returns and as "married" (either jointly or separately) on their federal income tax returns.
Yes. A same-sex married couple living in California must file as "married" (either jointly or separately) on both their state and federal income tax returns.
Yes. A same-sex married couple living in Delaware must file as "married" (either jointly or separately) on both their state and federal income tax returns.
Yes. A same-sex married couple living in Hawaii must file as "married" (either jointly or separately) on both their state and federal income tax returns.
Yes. A same-sex married couple living in Maine must file as "married" (either jointly or separately) on both their state and federal income tax returns.
Yes. A same-sex married couple living in Massachusetts must file as "married" (either jointly or separately) on both their state and federal income tax returns.
Yes. A same-sex married couple living in Minnesota must file as "married" (either jointly or separately) on both their state and federal income tax returns.
Yes, a same-sex married couple living in Missouri must file as "married" (either jointly or separately) on both their state and federal income tax returns.
Yes. A same-sex married couple living in Vermont must file as "married" (either jointly or separately) on both their state and federal income tax returns.
Yes. A same-sex married couple living in New Jerseymust file as "married" (either jointly or separately) on both their state and federal income tax returns.
No. Same-sex marriage is not legally recognized in Mississippi. A same-sex married couple living in Mississippi must file separately as "single" on their state income tax returns and as "married" (either jointly or separately) on their federal income tax returns.
No. The election to file single or married is totally yours, and able to be changed each year.