Residential Qualifying Period for Citizenship

I'm confused about when I would qualify for British citizenship. I am an American citizen married to a natural-born British citizen. My timeline follows:

I entered the UK on 24 Sep 2005 with UK Entry Clearance for Marriage, which was valid until 16 Mar 2006.
During that time, I lived in the UK with my then-fiancé, leaving the UK only once for 5 days.
We were married in the UK on 4 Feb 2006.
I received my Residence Permit with Limited Leave to Remain (FLR[M]) on 15 Mar 2006, which was valid until 15 Mar 2008.
I now have my Residence Permit with Indefinite Leave to Remain in the UK (SET[M]), as of 19 Mar 2008.
I fulfill the other requirements as far as age, being of sound mind, knowledge of the English language (passed the Life in the UK test on 1 Feb 08), and being of good character.
My question is when would I become eligible to apply for British citizenship? Would it be 24 Sep 2008, i.e. three years from the date I first entered the UK to live? I'm not sure if that's correct since my visa at that time was not technically a type of Residence visa - it was simply Entry Clearance for Marriage. Or would I qualify for British citizenship only 15 Mar 2009, i.e. three years after I was issued my LLR?
TIA!

jezroz, you are correct, it's the 24 sep 2008. The residence requirements for naturalisation do not depend on type of visa but on physical presence in the country.