It depends on where I'm going, how long I'll be gone, and what I'll be doing...
Standard operating procedure is to bring my 650mah Twist.
It always has a standard resistance 510 atomizer and drip tip perched on top.
If I'm going to be gone for a long period of time, I'll bring an extra 650mah Twist battery.
Standard operating procedure is to bring a couple of small sample-sized flavors in my pocket for dripping.
If I will be in the car for a large percentage of time then I bring a small drawstring bag with a bunch of sample-size flavors.
If I'm going to be out for an upscale night on the town where dripping would not be cool then I'll bring my eRoll instead.
This is very rare as I'm not all that upscale, and I don't give a crap who sees me dripping.
If I'm going to be out all day long doing highly mobile or physical things, then I bring my Mini Reo.
The downside is I am no longer running variable voltage and I am stuck with one flavor.