Those are all side issues to the issue at hand, which is what to add for flavor on top of well-balanced, healthy meals. FOOD IS OUR FRIEND.

Here's what I have so far, but I'd really like to hear more on others' "treat" preferences:

2 T jam, 90 calories
1/2 yogurt (3 oz.), 95 calories
2-3 t olive oil, 80-120 calories
4 T barbecue sauce, 80 calories
2/3 C unsweetened whipped cream, 100 calories
1-1/2 T honey, 96 calories
1/2 hardboiled egg, chopped, 105 calories
1/2 granola bar, crumbled, 95 calories
1/2 C cool whip, 120 calories
1 T peanut butter, 96 calories
1 T butter, 100 calories
1 medium banana, 100 calories
1 C apple juice or orange juice, 100-120 calories
1/2' slice jellied cranberry sauce, 86 calories
1/4 C craisins, 104 calories
1/5 C Raisins, 104 calories
1/4 C cole slaw, 93 calories
2 T maple syrup, 104 calories

T = tablespoon
t = teaspoon
C = cup

Source: http://www.calorie-count.com/

As far as "which kind of peanut butter, yogurt, etc.," I used the numbers for the full-fat, full-sugar varieties unless otherwise specified.

~Susan