Hm, my favorite tool at the moment is my superior thread spool holder, I can just go and go with that thing. Favorite machine feature is, well, the simplicity. I have a mechanical bernina from 1980, and I love that its always the way I left it the last time I used it. I had a computerized machine for a couple weeks, and since I too am in a small space, I have to put it away when not in use. It was infuriating that the needle position would reset every time I unplugged it and plugged it back in, I broke SO many needles! Wish list, is a design board.
Btw, those who need small space solutions, I found this ikea table and I have 2 on order. The will 'live' as end tables on either side of our sofa, and when I need them to quilt a bed sized quilt, I'll pull them out and extend the sides for that.
http://www.ikea.com/us/en/catalog/products/70290223/