LOV3MYC4R
20% off everything for Valentines Day @ www.powerbulbs.com with the use of the following code: LOV3MYC4R
The coupon code can be seen on a banner on the British website (as opposed to the /AU site). There is no end date stated, however, further down the page it looks like the expiry date is 20 Feb.
Don't forget, any item with a list price of $30 AUD or more gets a free gift. Delivery is also free.
Postage is reasonably quick and they've got the best prices for genuine bulbs that I've been able to find online when I was last looking for a new set of headlights.