Well there is a reason why they decided not to kill Hitler, because the man was a tactical goon and was leading Germany down the shitter.
If he goes, the Allies lose there main advantage, that Hitler insisted on controlling everything. The man who replaces him will probably listen to the generals, and that could lead to German victory (depending on the date anyway).
Though I think Hitlers assassin will probably be caught fleeing Germany, so he/she will be remembered for the sacrifice they made rather than for ending the war.
Anyway, the best Hitler assassination was in a film that I think was called "Hitler, dead or alive" where the assassins disguise themselves as waiters at a Nazi do. They grab Hitler, drag him into a room, barricade it, give him an all over shave, stick him in a waiters uniform and let the guards in. They cannot recognise the Fhurer and take them all away to be executed.