If you had to choose a single light shaping tool, you might do well to pick the silver, 7' Impact Parabolic Umbrella. First of all, it's a huge broad light source that wraps light around your subject, yielding clean highlights and rich open shadows. 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 structural design 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 all the light output is bounced back to your subject instead of through the umbrella. The silver interior provides a more specular and contrasty look than a white umbrella. You can also vary the light-to-umbrella distance along the shaft for a harder or softer light. In addition, an optional diffuser is available for this umbrella, which effectively converts it to a large softbox with just a 1/2 stop loss of output.
This silver version is ideal for throwing the light over a long distance. Two of them, for instance, could light an entire auditorium or a large graduating class. The umbrella features an improved finger-friendly locking mechanism for secure and fast set up and break down.