Every program that takes user inputs is better for offering custom keybindings. Being able to change keyboard shortcuts or add new ones (for example, making F5 refresh a page like it does in most browsers) would be great.

On a related note, as much as i appreciate being able to use my mouse to click links, i also like having the option to type a link's number based on how far down the page it is. This should be optional, in case people want their number keys to do anything else.