I find Lost incredibly boring, so it gets my vote. Love The Shield, which I actually find rather underrated. I loved Heros to start with, but it went into a decline by the second half of the first series which continued into the second season and 24 was great dumb fun when it started, but has become repetiteve and tedious by now.
The Wire is a great series, but recently I've become irritated by the "I'm part of the club because I'm watching The Wire" wankatons on here and on Urban it's being treated like the second coming rather than just a good TV drama. The hype here has reached oversaturation, people never seem to shut up about it while most have nothing interesting to say apart from "I'm watching it so I'm in with the gangstas and cool" or somesuch rubbish, so just on Urban I find it overrated now.