I really don't have an issue with "e-cigarette" like many here. For me, it is circumstantial, especially if a smoker is asking. If I'm out on the patio of a bar with other smokers, for example, if someone asks what it is I usually say "electronic cigarette" (I have an Ego with ego booster, which is pretty long, so I actually say Electronic Cigar). It's easier for smokers to relate and strike up a conversation... "I always wanted to see one of those", "I've heard of them", etc. If I say "it's my vaporizer", I've actually seen them apologize and move off, presumably because they think I'm an asthmatic or something and trying not to kill me with 2nd hand smoke. If I say "it's my nicotine inhaler", I would most likely get a funny look followed up with "So it's an electronic cigarette?". So I just cut to the chase.
Also, I can usually tell if someone is genuinely curious, or whether they are bringing it up because they are concerned/irritated. I have no problem calling it an "electronic cigarette" with someone who seems curious. Most people have heard of them, and almost these conversations discuss how it is not smoke. The latter "concerned" type, in my experience, doesn't want to engage in a debate. They want you to....stop making stuff come out of your mouth. With those types, I usually keep it short and say "inhaler" as it disarms them a bit.
I think a bigger disservice is for those who say "it's water vapor". It's not, and stating so makes vapers seem dishonest to the busy-body types; that we're un-informed at best, and that the public needs theses nicotine-infused chemicals need to be regulated.