When I was first building/designing my responsive site, I based my initial efforts on a slightly modified version of Joni Korpi’s Golden Grid System. It served me fairly well to begin with, but the way the media queries were set up made the layout’s reaction to changes in screen size never look quite right.
Needless to say I needed to make it work, and so I kept a lot of the underlying code intact, but pretty much abandoned the grid that was in use in that system, and came up with something that worked a little bit better for me. This allowed me to set a static width for larger screens and then adapt a little more naturally for smaller sizes.
Which is precisely the point in systems like that. You take what works for you, then adapt and modify the rest to better fit your needs.