I like both styles of dressing. I admire beautiful peacocks and disciplined minimalists. When well-done, neither are forgettable to me (i.e. when observing others dressed this way).
In personal dressing, I don't care what other people think. (Admittedly this is only because I'm out of the workforce. Dressing for the office is another thing altogether.)
I'll do both ends of the spectrum and in-between.
But using Angie's definition of "forgettable to the wearer" - I don't know if I've completely forgotten what I'm wearing. I don't mean in the sense of being aware of scratchy fabric, or poor fit, or self-conscious color or shape. I try to buy/wear things I really like, so it gives me enjoyment to look down and get a little pleasure from what I'm wearing - especially nice during an otherwise difficult day.