My accuquilt go.....

I can use up scraps in no time.. Perfect cuts, minimum waste.. My favorite currently is the 2in sq.. Great for making leaders and enders..

Binding clips. I love to hand-sew binding, and these hold it in place perfectly. I also use them for hemming. I think they are just unpainted metal barrettes. Self-threading needles for burying short thread tails. 1/4" seam foot WITH GUIDE-used a plain 1/4" foot for 20+ years, got a #57 foot for my Bernina 440 a few months ago. It just makes it sooooooo easy. Also two indispensible sewing machine features: needle up/down, preferably programmable, by button, AND as a function of the foot controller; and built-in dual feed (IDT)

I'd have to say the cutting mat is what I use most. Blue side for cutting of course but, I use the white side for piecing and placing applique (so the glue doesn't get on my table or the cutting side of the mat). Aside from that I would be completely lost without my sewing box. So many things got misplaced before I finally bought one! Never will I underestimate the convenience of being able to find what I use most ;)

Loooove my June Tailor shape cut ruler!! I just bought the one for triangles too. I never realized what a great tool it is!
I also love my bobbin winder. I sit there and co bobbins for all my machines so fast!
One more thing- I got a quarter inch foot for my Featherweight. Love it!

All of the above with the Shape Cut getting a big star from me, plus my SITD foot. Gives me a fighting chance of staying where I want to be.