I have a very basic machine with just straight and various zig-zag stitches. I've used all of them at one point or another, but in quilting, specifically, I pretty much only use straight stitches (longer or shorter based on what I'm working on).
I recently ordered a new machine with several decorative stitches. Once I get using that, I can almost guarantee that I'll be doing just that - using 20%, 80% of the time. LOL I'm looking forward to trying them all out though, and hope to use some of them when quilting.