I agree with Dumwaldo . . . the best vapor production tends to come from the less conventional looking e-cigs. Of my personal arsenal (Janty Kissbox, Janty Dura-C, Screwdriver, generic penstyle, generic DSE901, and PureSmoker Pilot), the Screwdriver is definitely the best in terms of throat hit and vapor production. (I have a JantyStick on order, and while I haven't yet tried it, I suspect it will provide vapor and throat hit similar to my Screwdriver, at least based on reviews I've seen thus far).
Having said that, though, I think many who are new to vaping are a bit more comfortable, at least in the beginning, with something that is somewhat close in size/shape to a cigarette.
With that in mind, I'd strongly suggest a 510-C (I have the Janty Dura-C). It's slightly longer and thicker than a conventional cigarette, but still close enough to a cigarette feel to keep most folks happy. It produces a good amount of vapor, especially considering its size. The other thing that's nice is the 510 provides a harsher vape, more reminiscent of smoking a tobacco cigarette than some other, smoother devices.
In my mind, the only downside to the 510 is the battery life is pretty short (for me, a couple of hours, sometimes less, but I'm a heavy vaper).
If you don't think that you need something cigarette-like to start off with, then I'd be looking at something like the Screwdriver, the JantyStick, or the Prodigy. I think any of those will pack a nice punch and provide more than enough vapor to keep you happy. Plus, their battery lives will put the 510 (and most other "traditional" models) to shame.
