Classify nicotine juice as a tobacco product and they won't be able to take it away from us. It may just be expensive.
If juice containing nicotine is legally classified as a tobacco product, it will be taxed, sure, but it will have the same legal protections as other tobacco products. It is unlikely that any tobacco product would be banned any time soon. Tobacco products are not subject to FDA approval, but they are subject to laws such as PACT.
PV's themselves, and substances such as PG and VG, 0 nic juice, cannot likely be banned or regulated, any more than cigarette lighters, hypodermic needles, sheets of paper, empty glasses or any other object that may or may not be used to administer a drug. Any law that does ban these kind of things could be challenged. If some cruel and absurd law like that does slip through, then I guess we'll have to figure out how to resuscitate dead atomizers and build mods ourselves.
If we are to fear the legal banning of e-cigs, seems to me that the main item of issue would be liquid containing nicotine. With an agreement between a juice manufacturer and a (non big-tobacco) tobacco company, e-juice could be distributed to tobacco retailers everywhere in the same way that tobacco products such as snuff, snus, or cigars are. It may not be at 7-11 but it might be at a cigar shop. You may not be able to mail-order it but you can pick it up in person.
Our current golden age of free-for-all mail-order cheap Chinese juice is not going to last no matter what happens. E-cigs are going to inevitably end up banned outright or regulated as tobacco products. Commercial interests are pushing to ban them outright, but if the industry itself pushes to get laws into place to consider e-juice a tobacco product, it could be protected from outright banning under the safe umbrella of the current legal classification of tobacco products remaining legal and free from FDA regulation.
I'd prefer cheap e-juice and not having to pay the steep penalty-style taxes on it. But I don't wish e-juice to be banned, so I would choose to pay more money for it than have to resort to brewing my own at home.