I do when I get a craving, so once or twice a month maybe.  Diet Coke, Coke Zero, or the Dr. Pepper that's 15c a serving.  I enjoy the belching that comes with the fizz, but that's just me!

MRM makes a vegan powder, and I was able to find it at my local grocery store. It's not the tastiest... but it has decent stats and its vegan.

http://www.amazon.com/MRM-Protein-Nutritional-Supplement-Vanilla/dp/B0052ONXWQ

I have a 20 oz bottle of diet coke on my desk right now.  I bought it 3 days ago and have taken about 3 sips.  I'm just no longer a fan.  If I drink too much at one time, it hurts.  I also have a bottle of water on my desk.  Now, that, I have to set a timer so that I remember to sip it throughout the day.  Coffee is my drink of choice, and there is none of that on my desk at the moment because I'm trying to get in more water.  I don't believe that soda stretches our stomachs.  I do believe that it has no nutritional value and can be dehydrating because of the sodium and caffeine content.

Hey, Marly.  I had my surgery in May of 2007 also, and had a re-gain of 45 pounds!  I'm happy to report that I was able to lose that plus some more!  My step-by-step instructions when like this.  1) Reconnect with WLS support group, attending meetings.  2) Attended Overeaters Anonymous meetings.  3) Met with a registered dietician familiar with WLS to get a workable food plan.  4) Return to some basics, like weighing/measuring; eating 6 times a day; not eating and drinking at the same time; removed trigger foods from my eating (i.e. sugar, corn chips, fast food).  Sometimes I took one step forward and two steps back.  It probably took me 6-7 months to re-lose all the weight, and even longer to become truly free from compulsive eating.  It doesn't take hard work, necessarily, but it does take consistent work. 

I haven't drank soda since having WLS except one time.  I didn't drink my one soda until I was around 18 months post-op.  I drank it and had lost the taste for it.  It tasted chemical and the carbonation bothered my pouch.  I drink water, iced tea and Crystal Lite and don't miss soda at all.

BTW, check out the OH Conference since you posted about it.  If you're going to go, the early bird discount ends on 3/27, so buy your tickets before then.  You'll make friends and create memories that will last a long time.