I've used many different shampoo bottles, and almost eveytime when it comes how to use up the last bit, it gives me a headache. I hate to waste but often have to dump the bottles with some shampoo left.
I like the idea of shampoo bottles with opening at the bottom, that way when you try to use up the last bit. It makes life so much easier. However, I agree that it's not the best solution when you have a lot left in the bottle -- the kind with press-down top is easier.
Would there be a perfect shampoo bottle for both situations?