Myself, I've probably wasted the most time of my life on StarCraft. In excess of 8,000 hours. Vowed to never do the same with SCII; so far have not.
Runner-ups would be C-S and FFIX. There are a lot of haters against IX, but I've found it the most enjoyable and strangely immersive. Comedic, deep, and goes back to the roots. None of that serious, emo, main character shit.