The bread at Jimmy John's is phenomenal. The only problem with there (and, if I remember correctly, Blimpie) is that they don't have the selection of toppings that you can get at other places. I pretty much just want some lettuce, mustard, and black olives on my sandwich.
I enjoy Quizno's, but not for their sandwiches. Their honey mustard chicken salad is really good, and pretty low-cal (especially since they put the dressing on the side). The pita bread that accompanies the sandwich is pretty good.
I know Panera isn't a "sub" place, but the Bacon Turkey Bravo is pretty much the best cold-meat sandwich ever.
Regular honey mustard chicken salad w/ dressing is nearly 1100 calories.
Small is roughly half that, but a still substantial 550 or so.
http://www.quiznos.com/subsandwiches/Menu/PDFs/NutritionalInfo.pdf