RE: Most important piece of equipment?
The most important tool is an X-acto knife with lots of fresh #11 blades. Don't buy a 5 pack or even an 11 pack, spring for a box of 100 blades and toss them frequently.
The next most important tool on my bench is the one that does a perfect job of beveling aileron stock. The Master Airscrew Razor Plane. Mark a center line on the stock. Hold the razor plane at the desired bevel angle and make full length passes. Count the strokes and stop short, do the same number on the other side. Now touch up as needed. It can't be beat.
Dave