I agree with fourthrok. Getting started, you may want to take it a little slow. I own a Twist and really liked it when I first got it. The variable voltage gave me a chance to try different juices at different volts. This was good, because some juices respond better with higher volts than others. I was able to get most of a day of vaping out of my 1100mha twist. Your mileage may vary, of course.
Of course, what do you do when your PV is charging? You use your backup PV! That means you'll want a good backup to use while charging. This means you'll want to get 2 Twists or Spinners. That's probably my recommendation for a low budget set up.
There are other options, using replaceable, rechargeable batteries. The mack daddy battery is the 18650. This has twice the capacity of the Twist/Spinners. Most people get a solid 24 hours of vaping off these.
One of the entry level items using this battery is the Gripper. This uses the 18650 batteries. They cost about $50 and will use any 510 gear.
Variable Volt Gripper, Silver
You'd need 2 batteries and a charger, sold separately.
If you have a larger budget you may consider a Provari (I own one of these also). However, getting set up with one of these will cost you about 200$ for the unit, batteries and charger.
Having a better idea of your budget would help us make recommendations better suited to what you want.
Of course, we are only talking about the battery/power delivery device. You'll also need good juice and a juice delivery system. I'm partial to carto/tanks. These are a tank, with a cartomizer inside. The cartomizers are replaceable (2-4$) and work well, when submerged in juice.
Here's an example:
Artemas Locking 510 DCT, Clear
There are lots of tanks. Most tanks are a form of plastic. These will work for most all juices, unless you like cinnamon or citrus juices. These sorts of juices can crack the tank over time due to the chemicals in them.
There are also Pyrex glass tanks. Pyrex is very durable and very hard to break. There are at least 2 good vendors for these: Phiniac (expensive) IBTanked (less expensive).
So, what budget do you have?
What juice delivery systems are you a fan of?