I would have said yes a couple months ago, but I have two hensels and often set up my 580ex and wish I had more lights/control.
You're going to wind up wanting a better softbox or at least a gridded softbox.
I now have two alienbee b800s on the way that I'll use with barndoors for BG or a hair light. And when my supplier gets more hensels in I'm going to pick up two more of them as well.
Umbrella's spill light everywhere and the modifiers you get from hensel are garbage anyhow.
I'm not saying you can't get good shots with that package, or even just one light and a reflector... it just limits you is all.
Matt
If you're sure you want to start this adventure, be prepared to triple that package's price in the next 6 months as you progress and want/need more out of your setup.