Depends how much vapour and flavour you want?
Everyone is different and different things work for different people.
Here is what I would reccomend:
10-30W - iStick/MVP etc and a Nautilus Mini (Ok flavour, little vapour)
60-80W - MVP/Istick 100W etc and a Aspire Atlantis 2 (Amazing flavour, very good vapour production)
40-140W Smok 160W and a TFV4 tank (Amazing flavour, crazy vapour production)
I am using the Smok and the TFV4 tank and it works grat for me, I like high wattages though but everyone is different.
I also use and RDA, but this is more advanced and you gotta know what you're doing, but the tanks and batterys I have given you are the most commonly used.
P.S. I highly recommend starting with something that is hand to mouth such as an iStick/MVP etc and a Nautilus Mini, this is because you imitate cigarettes more this way, where as something higher wattage is straight to the lungs and more for hobbyists (People who have quit the habit for good and use low nicotine) whereas and istick with a Nautilus Mini is more for people who are trying to quit smoking.