Breaking Bad. I have watched the series in it's entirety 4 times. More than any other show. It's my #1 favorite show of all time, right next to the likes of Prison Break, Sons of Anarchy, LOST, Dexter, Mad Men, Game of Thrones, etc.
The Wire is pretty good, but I wouldn't feel the need to rank it higher than The Sopranos or The Shield or any other similar show. It's a quality series, but it just doesn't have the special spark or phenomenal casting choices as BB that truly separate it from the rest. The Wire does have one thing going for it though -- it feels very authentic and gritty, and usually takes less artistic liberties than BB to keep the story interesting. However, I still find the "drama" of BB to be so much more entertaining, consistent and wholesome. There is a really good sense of dynamics and pacing and storytelling in BB that you don't get with shows like The Wire. Can't deny that The Wire is a very well written show though.