though I also got some others, mostly for their looks...
Don't I just know it you beat me to them by a hair.I have to admit tho after seeing what happened to darkgears my ardor to possess one has cooled a lot.I ordered a silver pv1 instead not two minutes after reading Stormy's review.
Now back to thesandmans question.
If you order the Provari kit it will come with a protank 2 and there are a lot of people that love them and most of us are familiar with them.
Next step are carto tanks, Ibtanked pretty much are the hands down favorite at least on this section of the forum, very popular are also
Phiniac tanks, cirrus tanks and I have the feeling once they become more widely known the PV1.
There is an exellent tutorial written by Batitude for priming and filling carto tanks.
http://www.e-cigarette-forum.com/forum/blogs/baditude/3710-5-cartomizer-tank-setup.html
Next are the step up from the carto to the Killer, Diver, Sophia and the Rose, there inserted instead of cartos in to a tank but you build your own coils for them. I'm still to much of a noob myself to use them.
The creme de la creme would be the Kayfuns be that 3.1 or light or light plus, the russian 91% usw. for that and the Killers and divers usw. you need a knowledge of ohms law , you got to know how to build coils and you better have an ohm meter.
Someone will be along shortly without a doubt that knows way more about this than I do and will explain this much better then I ever could.