You asked in another thread on the same forum, and really, people can tell you their preferred model, but it needs to be said:
The "best" is
really subjective.
There are a lot of good models out there (510, KR808, 901, 801, M401...I could go on...and then there are the mods...) and each person has their preference. Check out
The Wonderful World of Vaping as an intro if you haven't already as it has pictures and descriptions of many models.
But if you really insist on a specific answer to get going right away...
A common model to begin with (and the one a lot of people stick with, too) is the 510, and one of the things people recommend most is the no-box $35 kit from
Cignot. Grab a bunch of juices while you're at it, and just see what you think, and ask questions/search for topics here.
The 510 is a three-piece unit: cartridge, atomizer, and battery.
But not everybody likes fiddling with cleaning the atomizer and filling the cartridge, etc. So some people prefer two-piece models like the KR808 (the Vapor4Life model keyzygirl mentioned), which has a disposable "cartomizer" (a long lasting unit that holds a lot of juice). They're great too.
That's just the two models I am familiar with. Other people have their opinions based on their needs. Once you take the plunge, you'll either find you're happy, or you need to switch -- but you gotta start somewhere, right?