Hmmm, I think my record is less than a day to watch Queen InHyun's Man...but one of the perks of cable dramas are 45 minutes episodes, which are always easier to get through than the hour long eps. If I'm really into a Jdrama, I can usually finish it up in a day
My first drama was BOF though, and once I got hooked, I'm pretty sure I watched episodes 4-22 in a day :P