The Wire is number one for me, and it's not remotely close.
After that 6 Feet Under, Breaking Bad, Sopranos, Mad Men, Seinfeld, Band of Brothers, etc. Splitting hairs to rank all the serial dramas against each other.
I've never seen 6 Feet Under but I agree with this. The Wire is the best show I have ever seen. I'd agree with the rest of your ranking too.