I would suggest Daphne retusa, one of the smaller ones flowering now.

I agree, and probably one of the easiest. D. tangutica runs it a close second. For sheer magnificence, though, try and get hold of daphne bholua 'Jacqueline Postill'. Once established (and it may take three to six years), it'll flower with real exuberance, and the scent is exotic. Makes a medium sized shrub, about 6ft high. There should be some small plants available later this year, but they're scarce at the moment.