my favorite ruler is my fluorescent 24x6.5... the laser cut lines are very accurate and easy to see. i wish i had gotten all of my rulers in that color. i don't use my slotted ruler very often... i find that my accuracy is a little off because the lines are hard to line up on square. that being said, when i need to cut many many small squares, the slotted is great to get it done more quickly. a large square up ruler is a necessity if you make larger quilts. for squaring up hst's, i use my 6x6, again wishing it was fluorescent instead of the yellow and black lines. hope that helps. and welcome to the board from MN