Thank you all for your responding and weighing in on this issue. Vast majority are just like me - wanting to make the block/unit just a bit extra big, even though I, too, hate trimming, for the benefit of getting the perfect size unit/block. Like some others, I have found Bloc-Locs to be the most awesome ruler for trimming HSTs. I also have some of their other rulers, and love them all! They are a bit pricey, and for that reason I recommend people getting a bit bigger ruler, so it can be used to trip many different sized HSTs. However, I believe it is still money really well-spent to buy one!
Last Friday I was at a quilt show and came across a ruler I hadn't seen before - it is called a "V" Block Ruler by Deb Tucker (someone mentioned one of her other rulers on this thread). I had been writing a new pattern, and it uses V Blocks. I have always used Tri Recs Tools for that, and while I was writing this pattern I was trying to "over-size" the pieces to make them "trimmable", with not much success. So I was very pleased to see the V Block Ruler demoed, as it makes perfect V Blocks with ease! Now I just need to adjust my patterns, as in order to get a finished 3" block you start with a 4" strip, rather than 3.5" strip. Just so nice to see more and more tools that help us make pretty quilts come out!