Truth be told I'd gladly watch Kamen Rider W for a 4th time. *glances at avatar*
But it seems like cheating to just say I'd rewatch something that I have on my own Favorite Dramas list, so I'd go with Dr. Frost. The premise sounds kinda like Black Jack meets Bartender (i.e. it sounds more like a J-drama, including the shorter 10 ep length).