The most useful two options I've found for starting up emacs are:
-debug-initThe first disables the loading of your .emacs and default.el files, which is handy when you want to differentiate between problems in your .emacs file and problems outside (.Xdefaults, site specific .emacs, etc.).
The second gives you a backtrace when any error happens during loading of your .emacs file. While it doesn't often pinpoint the exact line where things went wrong, it usually gives you a clue as to where to start looking for problems.
For all options, read the manual here: Initial Options - GNU Emacs Manual