I thought Sensodyne didn't help at all and also the mint flavour is so mild it's pointless using it to freshen your mouth in the morning... even the extra cool one.
I found that Colgate was the best for sensitive teeth, which I use for a couple of days when I get sensitive teeth and then go back to Aquafresh whitening as I find that's the best for whitening, strongest taste and makes my mouth feel the freshest for longest.
I know it sounds wierd, but unless the toothpaste tastes really strong, I only ever brush my teeth with Colgate sensitive at night before i go to bed and it works a treat (I've not had any dental work in all my 31 years, brushing twice a day with a normal toothbrush!!!