There are times when I am instantly drawn in by a color scheme or fabric, but I can also be guided by the pattern. When I started way back when before rotary cutters, my how-tos and reference books were mostly in black and white with diagrams, like the newspaper patterns. Typically they didn't even show you layout options or what you could do with the block -- just the block.
I love seeing how different fabrics/color schemes can make the very same quilt look very different. Likewise, with block exchanges and final projects. One of my favorite parts of any guild show is if they have a mystery/chosen colors project. I know I love seeing the what the other quilters are doing on things like the Bonnie Hunter mysteries -- even if they have me second guessing or not-so-excited about my own choices.