ok i just saw a thread where people were talking about the opening titles and what they meant...and they didn't come to a conclusion. So i thought i'd post what i have believed since the 2nd episode of the first series (after i got to know the characters :P)
The Adam and Eve one: This is Susan and Karl. Susan is portrayed as the innocent, naked (here meaning open) woman. The apple falling is her bad luck in the 'male dating' area.
Egypt and the kids: This is lynette. The kids appearing is her mentality that her kids are taking over her life and she cannot escape it.
The American Gothic (farm building with old ppl): This is Mike (i think, i cant remmeber it totally), but in series 1, Susan and Edie were both vying for his attention, and therefore he was probably going between the two choice-wise.
Lady in Kitchen: This is bree...she carries the shopping, and is the stereotypical housewife and mother. However...the shopping falling is an indication to how her life slowly crumbled around her in the 1st series.
The arnolfini portrait (pregnant lady and the banana skin): This is edie and martha (i think) because edie was always taking from martha, and martha just went along with it. (edie throwing away banana peel and martha cleaning it up)
The Lichenstein one (cartoony): i think this is mary-alice, possible gabrielle and carlos. The fighting is a representation of violence, and therefore seperation and anger.
I don't think there are any more scenes...i always forget the opening titles...if i have missed any post them here and i will tell u

I hope this clears some things up :S (btw i didnt copy this from anywhere, this is my own opinion...)