For straight measuring and rotary cutting, I do not believe you can do better than the Quilters Select rulers made by Floriani. They absolutely DO NOIT SLIP. I had used Creative Grids (marketed as non-slip but they do move) until I found these...............
For technique tools (specialty cuts like a diamond in a square, for peaky & spike types, etc.) I think Deb Tucker's tools are the very best for accuracy. You can view her items and watch videos on how to use each on her website - deb tuckers studio 180 design.