For around the house, and so people won't use mine, just about every room has a pair of cheap Wal-mart ones. Have a pair that is grey/yellow and they are the sharpest in the house. As for sewing/yarn/quilting, I have a pair for each craft. I use my mothers old Joy pinking shears when I need pinks for paper, my Fiskar pinks on fabric, and all my other scissors are Fiskars including the 'new' ones for rag quilts.
My one pair of Fiskars get sharpened about every 6 months. I run it through the little sharpener you can buy at JoAnn's.
I have a pair of embroidery that are Ginghers and they won't stay sharp for anything. Really irritating!
For those of you who have family that borrow your scissors and don't listen or respect your requests not to use-why not hide them in your fabric bins/drawers/etc. under fabric?