eGo is a good place to start, or the eGo Twist if you want a cheaper alternative that also features (very non-intrusive) variable voltage. The Vision Spinner is also on that list, it's more or less a Twist look-alike but with slightly easier to read settings.
What Burd said can be true. Some move past that onto something more complex. Some don't. I never did--I have the more complex stuff, but tend to go right back to my old unit.