Another vote for 2-3 days here. If I can take the entire weekend off, I can get an insanely great shave monday morning if I do my part. (I'm still enough of a newb that I screw it up sometimes!)
I get such a close and long lasting shave when I do this, though, that I tend to have a rough time shaving every day after that. Going for BBS 3 pass shaves every day is still a little rough on my face. By Wednesday, I might get a decent amount of irritation in the morning.