Low carb Products, whether they deserve it or not, sometimes get a really bad reputation. It's easy to see why , when some dietiers buy all the so called "low carb" products they  find in attempt to live the life they always had. That's pretty much  is the opposite of a  lifestyle change.  At the same time, there are some good ones out there, that I think fit in really well to a low carb diet, as long as you're not against artificial sweeteners:

1.) Sugar Free Coffee Syrups:
Da  Vinci, Torani, Artista- they're all bottled syrups designed for cofee and sodas, but are far more useful than that. I  have a liquor-cabinet sized collection of this stuff! They're good in protein shakes, salad dressings, I've even seen meatball recipes that call for them. Most of them are splenda- based. 
2.) Heinz one gram ketchup 
I could make my own ketchup, but it never stays blended. and it's so good on scrambled eggs or this: http://www.genaw.com/lowcarb/moms_crazy_cabbage.html
plus  combined with dill (not  sweet) pickle relish, mustard, and mayo, it makes the thousand island dressing I sometimes miss from childhood.

3) low carb tortillas/pita breads 
Hey,  these are just  easy to make a meal more interesting - the low carb pitas are great stuffed with salads and whatever protein I've got left over, plus they're a way of working in a little more fiber and  omega  3's because a lot of  them are made with flaxseeds 

Same category  but a little different -  low carb crackers like these:http://www.brancrispbread.com/default.aspx
These are heaven sent when i'm ill and can't stand the thought of real food.They're also great snack with deli meat or tuna and a little cheese to keep it in place, and phenomenal with smoked salmon and cream cheese. Once the fiber, protein and  fat  hit your stomach, your're full for hours, especially if you  drink a  big bottle of water with it.
The trick is to watch your portions! I try to keep it to low carb  bread product per  day, if that.

The next pair are treats, not for everyday use.
Big Train Frozen mocha mix 
Spendy  but  incredibly  delicious - better than most mochas with actual sugar!
Sugar free chocoalte: yeah this stuff is available anywhere nowadays and taste-wise it's pretty good.It's also easy to let this stuff get out of control. As far  as this stuff goes, I consider this a trigger food that I try to really limit!

Well, there's my  shortlist.  Here's the ones that are not essential but can sometimes help in a  busy time or while travelling :

Atkins  bars  - these range about 250-300 calories and there's not a lot of food  for that fairly high  level of calories. I'd rather  just have bunless cheeseburger, a  can of tuna or a naked hot dog- they keep me from getting hungry a lot longer. However they can come in handy on long rides and work days  as long it's not a hot day - they melt  fairly easily.

Atkins Shakes - yeah they're convenient, and the Dark Chocolate Mocha is  awesome when  blended with espresso, but they're EXPENSIVE!

Carbquick - no slam on the product, but  biscuits and pancakes are what got me fat in the first place, and I've  lost my taste for them. I'd  rather have my eggs over a  big  pile of steamed spinach. However, it takes very little to make "impossible pie" an easy  form of  quiche that  my hubby loves!