Depending on what the quilt is for I will use just about any of the methods mentioned above. The only one I don't use is leaving the bobbin tail long on the back since I tend to have problems with thread nests when I do that.
If the quilt will will be used and subjected to lots of washing I do a combination of tiny stitches and backtracking to start and stop.
If it is an art piece that will be mounted on a stretcher or panel so the back is completely hidden then I tend to use my machine's thread cutter button which pulls the threads to the back, knots them and trims them short.
If it's a wall piece that will be hung using a sleeve, or hung using some other method that leaves the back exposed, then I bring both threads to the front, knot them and then bury them. I do this as I go-- it doesn't slow me down all that much since I also use that pause to decide where I'm going next.
Rob