A couple of my favorites are:
- Control+Space (to auto-complete)
- Control+1 for "quick fix", when your cursor is over a red-underlined error.
- ALT+SHIFT+R to rename a variable or method is also very handy.
In general (not Eclipse specific), the fastest way to select text is to hold down on the SHIFT key while using the keyboard arrows (or home/end), instead of using the mouse. Then you can use the usual Control+X, Control+C, Control+V to cut, copy, paste.
Also, if you look through the Eclipse menus, almost all of the actions have a shortcut key assigned to them, which is listed in the menu item...