Almost Mrs Average on the Rubbish Diet directed me to this very moving video from Beth Terry of Fake Plastic Fish. I would urge you to watch it ... and then challenge you to give up one plastic item for ever.
I've bought myself a small aluminium water bottle which I have begun carrying around with me to avoid having to buy bottled drinks. I am now going to follow Beth's example and invest in a travel mug for those occasions I pop into a cafe for a latte.
Why don't you let me know what you'll give up?