Here are the ways the Eclipse documentation states you can navigate the Content Assist list:

You can use the mouse or the keyboard (Up Arrow, Down Arrow, Page Up, Page Down, Home, End, Enter) to navigate and select lines in the list.

But all of the options require you to move your hands significantly away from their natural place on the keyboard!

Are there any other, quicker ways I can navigate this list? Something like tab, or the j/k from vi?