I like me a big roll of elastic so I don't waste so much using the precut hanks.
I borrowed Natalie's tip of taping a tape measure to the front edge of my sewing table. I used a free IKEA tape measure and used clear packing tape. It's helpful to not have to get up to measure waist elastic and stuff like that.
Thread racks for spools and cones to hang on the wall.
Little plastic IKEA boxes to organize stuff like labels, snaps, FOE, tags, zippers, ribbon, etc.
I love having lots of extra empty bobbins so I don't need to go hunting for one.
Magnetic pin grabby thing rocks!
Tara