The Ego or Ego type unit is a great place to start. Very versitile and dependable. I currently use the vision ego clearomizers, minimal fuss, very easy to use. I also use a 3ml tank system with my ego, after filling, very hassel free.
Ego or Ego type batteries are easy to find.
volcano sells a 3ml tank, tank cartomizers and the tube sock. The tube sock fits between the battery and the tank for a flush look.
http://www.volcanoecigs.com/tube-sock.html
http://www.volcanoecigs.com/inferno-orings.html The o rings works to keep the tube sock secure.....can be used with the ego batteries.
http://www.volcanoecigs.com/tube-tank-replacement-cartomizer-1.html
http://www.volcanoecigs.com/tube-tank.html
The tank system can be used with volcanos batteries or with ego/ego type batteries.