Day 29 is current TV show obsession.
The sad answer to this is I don't really have one at the moment! I think most people following this LJ can figure out that BSG would have been the most recent answer to this, with Lost nipping at its heels (though in a different way), but that BSG fervor has died down a LOT (mostly thanks to season 4.5 and the finale) and nothing's driven me into that sort of fannish frenzy since. So I guess I'll just go with the show that currently has me eagerly awaiting each new episode, sad it's not on every night, and reading reviews and commentary online:
Mad Men.
Show with the most potential to become the next obsession, depending on how next season goes? Fringe.