I think the nature of taxing makes ecigs very appealing to the government but that must be approved by congress. Due to the complexity of nic juice and DIY it will make for a complicated law, taking years to write and effectively put into full force. Fingers crossed.
E-cigs will NEVER be banned outright! This being the lesser of "two evils" (the other being tobacco), there's no way a ban on e-cigs will ever happen. Think about this and let's consider some history: alcohol was banned, ban repealed, assault weapons were banned, ban repealed. And if you do some research, check out this link that applies to my list
http://en.wikipedia.org/wiki/(insert the spelling for the illegal smoking material here, using an "h" instead of a "j")_Tax_Act_of_1937 Also, and most importantly, if tobacco products haven't been banned, there's no possible way government could rationalize the banning of e-cigs.
As others have posted, it's all about tax revenue. Cash, cheese, bucks, Benjamins, green, bones, clams, cheddar, dough

...the stuff that makes the world go 'round! BT and BP have seen that there is money to be made in the e-cig market and they want their piece of the pie. I highly believe that in the near future we will see BT enter the market with Marlboro, Salem, Camel, etc. brand juices from their respective manufacturers. Same goes for BP, Nicorette e-juices and the like.
I would speculate that BP and BT are behind the FDA inquires into the e-cig industry. Most likely all of this will lead to more taxation and regulations on e-cigs. This is inevitable! If the history of capitalism and our government finding a way to tax a product has taught us anything and there's money to be made on any product, the government is going to make sure they get some of the proceeds with taxation.
I am going to make a very bold prediction! E-cigs will never be banned, period!
--There will be added taxes and regulations (
eventually, but as Unc said, "Due to the complexity of nic juice and DIY it will make for a complicated law, taking years to write and effectively put into full force." And I must emphasize the part of taking years, as slow as our congress moves, these taxes and regulations will take
at the very least 5 years to enact).
--We will pay more for our e-juice...someday.
--Vaping will become more mainstream with the publicity of a possible tax. This will be reported in the media and by vaping advocates giving vaping a much larger profile than it has now. The vaping community will grow and even though there will higher taxes, this will even out in the long run due to a highly competitive market, such as it is now (being competitive).
As I see it, all of these inquiries by the FDA are a good thing. They will lead to more comprehensive studies on the effects of vaping and quite even possible advances in the quality of e-cig products. The "Chicken-Little" proclamations being made about vaping are IMVHO, "Much Ado About Nothing". I'm not minimizing anyone's concerns by any means nor am I saying they are over reacting, but in essence, I believe the "proverbial hammer" is not going to fall as hard as some may believe.