I've seen a few posts claiming The Wire's superiority but I have to disagree. Admittedly, I've only watched the first two seasons of The Wire and about 70% of The Shields run but the reason why I think The Shield takes the trophy is because it feels more "real". There's something about The Wire's structure which is a bit clichéd (even when it tries not to be clichéd) and it has certain elements of soap opera that is the downfall of a number of so-called great TV shows (The Sopranos comes to mind). The Shield on the other hand is consistently inventful and at the same time gripping with a sure touch in the way it handles it's pace.