Welbutrin (aka Zyban) worked like a champ for me. I have a real hard-core nicotine addiction with strong and obvious physiological withdrawal symptoms, but Welbutrin blocked all of them like they weren't there. The patch & gum did next to nothing for me. Of course, I'm back on the coffin nails (less than ever, FWIW) but know I need to quit.
But Zeus's advice is the most important - never have that first post-quitting smoke!!! You will want it, you will make all sorts of excuses why it's ok to have it, but they are all lies you tell to yourself. Don't believe the liar! He's evil!
Think like the recovering alcoholics do - don't try to not smoke for the rest of your life, because you will never think it's possible. Just try to go another day without smoking - that's a lot easier to accomplish! Then do it again.
Good luck!