I lost 75 pounds beginning April 2004 doing the South Beach Diet. I am about 25 lbs over my lowest weight right now and still mostly stick to phase II and III foods with an eye on the "Eat This, Not That" strategies. For snacks, I eat nuts (almonds most of the time, lightly salted cashews when I am craving salt), fresh fruit, 2% Cracker Barrel Extra Sharp Cheddar, and Fiber One bars. I eat a lot of grilled chicken salads and play around with romaine lettuce wraps but don't have the luxury of packing lunch most days. Check out the whole wheat sandwich thins, pocket breads, etc. The trick is to have the % of fiber >> % of carbs. Mustard and most other condiments do not have a lot of sugar - Heinz does a reduced sugar ketchup.
Eat This, Not That has been a great resource -
http://eatthis.menshealth.com/home