My first foray into vaping was with some off brand 'replacement cigarette' from a gas station convenience store ... I don't recommend going that route
I did more research after that and went with a 510 T battery because of the longer battery life. Most of my friends at work like the plain 510 or 808 (similar diameter to a regular cig), but I can't give up the heat and hit of the bigger batt.
I hate cartridges, but a standard atomizer with a drip tip can work well. I've pretty much gone over to cartomizers/clearomizers (atomizer + cartridge in one piece) which hold more juice than any standard cartridge.
Some people love the tank atomizers, which use tubes to hold more juice and don't include any cottony filler...but many people have had trouble with these so I'd stay away until you're more familiar with everything.
I've only been vaping for a couple of weeks, but I'm already looking for a more non standard mod that includes variable voltage settings so I can better control my hit.
Vaping did get me completely off smoking, 1st day I had maybe 10 cigs, 2nd day 3, 3rd day 1 and none since ... now they taste horrible, smell horrible and generally turn me off, how crazy is that for a 20 year 2PAD smoker?
Good luck with everything!