If you had to choose a single light shaping tool, you might do well to pick the Impact 7' Parabolic Umbrella (Black/White).
First of all it's a really huge, broad light source that wraps light around your subject yielding clean highlights and rich open shadows. But due to the special shape of the umbrella there's a unique mix of soft enveloping light with the kind of crisp detail you only get from reflectors. Put another way, if you combined a beauty dish with a softbox, you'd have a parabolic umbrella.
This umbrella has a unique design structurally as well. The shaft is reinforced for strength and instead of bendable metal, the 16 inner ribs are made of durable fiberglass. The fixed black backing ensures that all of the light output is on your subject instead of through the umbrella. You can also vary the light-to-umbrella distance along the shaft for a harder or softer look or for longer throw capability. With the Impact 7' Parabolic Umbrella less is definitely more.
7' Parabolic Umbrella (White/Black)
Carrying Case with Strap
1 Year Manufacturer's Warranty