One of my favorite quotes from Elly Sienkiewicz's show and book seems to apply here. This is something about which wise women can disagree.
But I'm going to vote to help even it out. I don't prewash. A few reasons: 1) I like the body of unwashed fabric. I even starch my unwashed fabric. 2) Like Harriet Hargrave and Margo and others, I like the patina and shrunk-up look that new quilts get immediately after their first washing when they shrink as a complete project (especially with a 3-5% shrinking batt). And 3) I don't know that prewashing solves a color transfer problem. I don't think that color bleeding into the washwater is big a problem. Nearby fabrics retaining the color would be a problem for me and there are products that might help block color transfer better than prewashing does.
And I generally buy good quality fabrics from reputable quilt stores.
And I'm knocking on wood a little here too because I haven't had any big problems yet...
I prefer straight grain binding for most projects, I sometimes press seams open, I like turned-edge applique stitched by machine, I fussy cut pieces off grain if the design suits me, I use monofilament thread, I don't pin a lot, I dry my quilts part way in the dryer, I shouldn't type too much before I go to bed, and I love reading what everyone has to say in the forum...