Obviously the answer is the invisible car. However 'Die another day' has many other amazingly terrible bits.
1) The bit where that sled thing goes over the cliff and Bond emerges doing a bit of kite surfing rendered as an N64 in game character. Dear God, that was shite.
2) The bit where the bad guy parachutes into London with a Union Jack on it as homage. If an MP ACTUALLY did that, we'd hang them.
3) Madonna's theme tune and subsequent guest appearance. So unnecessary.
4) Bond's Glass Shattering Ring. Why would you need that unless you were a lazy double glazer? I mean, it's not like there'd ever be a situation arise where you'd need to use it to evade trouble...
5) The fact the bad guy fences. FENCES. Those things can't even hurt a fly.
6) Jinx. Spin off potential my arse.
7) Bond surfing. Bond should NEVER surf.
8) The whole sun storyline. And that suit graves wears. And the guy with diamonds IN HIS FACE. And....
I remember this film loads better than I ought to having only seen it once?
To address the balance, here are the good things about it: The hovercraft chase. The bit where the ejector seat flips the car over. Rosamund Pike's bottom.
What bits in Bond films do you hate (cue someone like Mr. Biscuit saying 'all of them')?