So while you SHOULD be watching Lost, I can't in good conscious recommend Alias. This week's episode was truly bad. They've totally lost track of the characters. Not enough action. Too many close-ups. Far too many "significant looks." (Okay, maybe Alias has always had that last one, but the fast-pace always distracted me from it.)
I do recommend watching the seasons 1, 2, and 3 DVDs of Alias, though. Good stuff.