The genus Helleborus is unique in the world of perennials, and likely I would suggest, in the world of gardening as a whole. Their very early bloom time is essentially unparallelled. I can only think of Cyclamen coum, and a few of the early spring-blooming bulbs, as possible equals.
It was not long ago that Helleborus were relegated only to specialty nurseries, and at somewhat excessive prices. Nursery propagation was slow and tedious to say the best. In recent years however, they have thankfully become more readily available, and at more reasonable prices.
One of my favourites of a few years ago, is Helleborus Ivory Prince™ ('Walhelivor') from David Tristram of the UK. The bronze-pink buds open to a creamy-green-white flower, and their production is prolific.
More recently, I'm eager to try H. niger 'HGC Josef Lemper', a selection of the historic Christmas Rose by Joseph Heuger of Germany. The bright and pure white flowers are more upright and longer-lasting than older forms. I've even seen it available as a "pot plant" in some of the local grocery stores in December!
Finally, one that is "hot off the presses" and has many in the industry more than a little excited is H. 'Walberton's Rosemary', also from Mr. Tristram. It is supposedly a cross between H. niger and H. orientalis, which until recently had been highly sought after but nearly impossible to achieve. In any case, the flower colour and habit appears to be impressive.
You can read more about this beauty at Graham Rice's post, here.
In the meantime, here's to dirt your nails -- spring has finally arrived!