The better an eraser works, the less you will know it was used. The most ergonomic eraser is the one the removes the type of mark you have made from the medium you made it on with the control you need. This list should help you find the best eraser for the job at hand.
The Pink Pearl eraser is an oldie but a goodie, and it is a prime example of how good ergonomics can withstand the test of time. Not only is the eraser a great product, but the form factor is top notch. It just goes to show that you don't have to mess with a good thing.
If you find yourself needing to erase a lot, and your pencil top eraser just won't cut it, the Erase-It Eraser Stick is the answer. This eraser works just like a pencil and is a handy companion for mechanical pencil users.
Maped makes some great art and drafting erasers and they have brought that expertise to the school supply market. This is a cool eraser. Its extruded triangular shape makes it ergonomic and fun. The vinyl eraser is great, and the slip covers add some personality.