I prewash the fabric (as soon as it comes home from the fabric store). For the most part I purchase high quality fabric because I'm putting in a great deal of time and effort into making a quilt and to chinch out on fabric quality isn't an option for me. I do not starch unless I have a fabric that just seems flimsy and I am having trouble with. I will also starch slightly if my seams don't lie down well (as they did not on the bargello quilt).
For me starch is a tool when issues arise, not something I use all the time.