I tell my students this all the time: If you don’t start your designs with a grid, then you’ve already screwed up. I don’t care what you’re trying to accomplish, you need a grid. Sure, you don’t want that grid to “own your ass”, so you can always intentionally “break” that grid after establishing it. But opening Photoshop / Illustrator / InDesign / Fireworks / etc. without any idea of how you’re going to lay something out is going to kill you in the end (and your designs will most likely be crappppie).