if you intend your quilt to be washed, and who doesn't, then you should definitely wash your flannel first. even if you're of the unwashed school of thought. flannel shrinks more than other cottons, so wash and dry at the hottest temps available. i think you'll find that flannels feel tighter and softer after you wash them. you may still not be satisfied, but there will be a difference.
to my mind the flannels called chamois are the thickest and therefore the warmest. they are fuzzy on both sides, so you pay a premium price while you only end up 'seeing' one side.
nobody has the same idea ofwhat quality satisfies them. maybe you should buy 1/4 yds. of varying weights, wash and dry, and see for yourself. keep track of where and what.
EDIT: if you see something you like, but don't trust the quality, call the 800 number of the site. a salesperson will usually hear you out and help you make an informed decision.