as a basic rule of thumb anything with glossy leaves and evergreen shall tolerate the shade, the damp is little more awkward. Also any woodland shrub that is classed as an 'understorey species' shall tolerate the shady as well.
Being a fan of native wildlife, i'm going to contradict my basic rule of thumb and suggest a hawthorn, nice blossom in may, light green foliage throughout the summer and blood red berries to keep the birds going through the winter.
though technically a tree, it quite happily ignores the odd harsh prune or trim (tis a very common hedgeing plant)and continues to grow.
Suppose this depends on what you find nice to look at, i love the tree, you may not, but hey-ho, we're all different. Besides, hawthorn prefer well drained soils, but is only a preference and will still grow happily enough in the soils you describe.

If the soil is acidic a Rhododendron or Camellia would do very well there, almost perfect conditions in fact.

I planted a damp shady border last year, and put in Mexican Orange Blossom, dogwoods (red stemmed and a variagated), mahonia, garrya elliptica, er . . . . there was more . . . oh, it was the most expensive thing; mind's gone blank . . . well, I think it would be too big eventually anyway (ah, corylopsis of some kind, that's what it was). But the Mexican Orange Blossom might be just right for you. Like YewTree describes, it does have very glossy leaves!

i beg of thee, please advoid planting the rhododendron!

YewTree why not a Rhododendron? OK if unlucky then they may end up with Sudden Oak Death in their garden but thats quite unlikely. As long as the soil is damp and not WET which at times can be abit of an issue with them.
Personally I would be tempted to plant a FATSIA JAPONICA suitable for shade has attractive shaped evergreen foliage and rather unusual flowers in late summer. I have quite a large one (no rude comments please) which I cut back if it gets to big.

I love rhododendrons. I have just bought a beautiful specimen called Elizabeth. It has lovely red flowers and blooms in april rather than may. I also have a pink one that has done very well in my shady garden. I also like the Fatsia.
Alison

The problem with rhododendrons, hmmm, where to begin. Ecologically speaking the rhododendron is a bomb and is singlehandedly desimating the british countryside. It grows thick and fast and smothers out all other life, no native plants may live and saplings have the chance to grow. It has a sybiotic relationship with a fungi that lives around its roots which causes localised poisoning of the soils, again killing all native wildlife. The damn thing is also poisonous so nothing can actually eat it, and you might think that having one in your garden that you prune and keep in check won't be a problem, but the seeds blow everywhere and they don't take much to get going and basically wipe out and kill out native woodlands and associated life.
there is a popular past time which is becoming more and popular with the public, known as rhodie bashing, huge teams of people go into woodlads with chainsaws, machetes, bill hooks and detroy all rhododedron (one of the most common conservation projects) and burn the stuff, i've spent many a happy weekend doing this, and then poison the stumps afterwards (a very specific poison that is vegetative)
Though beautiful, the rhododdendron is deadly to britain and its natural landscape

sorry

YT

Rhododendron ponticum is an aggressive invasive menace, so plant one of the other hundreds of species or thousands of cultivars.

Personally, I'm not a great fan of most of the Rhododendrons that you see in garden centres and prefer the large-leaved types such as R. sino grande and R. macabeanum. However, the only pest species is R. ponticum and it is unfair to tar all of them with the same brush. Many of the Hardy Hybrids such as 'Pink Pearl' 'Scintillation', 'Cynthia' etc. do not seed themselves about. The smaller Yasimanum hybrids together with the compact forms derived from them pose absolutely no threat whatsoever, nor do the other ornamental species.

The explosion of Rhododendron ponticum in moister parts of the coutry is in part due to it being mass planted on country estates during the mid and late Victorian times. It is probably the most aggressive of all of the Rhododendrons and is highly opportunistic where conditions allow. Although a large plant is capable of producing many millions of tiny, wind-borne seeds every year, The main method of spread is by the layering in the wide-spreading branches, since the seeds need fairly specialised conditions for them to germinate (poor, acid moist soils with little or no established, competing vegetation). The layering of lower branches enables a plant to 'frog hop' many metres in almost every direction and develop into a huge, impenetrable mound in relatively few years. R. ponticum should never be planted I agree, but that does not mean that there should be a moratorium of the planting of all Rhododendrons.

As to the toxins in Rhododendron, it is true that all parts are toxic in those species that produce them, however a great number of garden plants are toxic to a greater or lesser degree, so that needs to be put into perspective. The jury is still out as to whether the toxins, when built up into the soil inhibit the growth of other nearby plants. The answer is to rake up the dead leaves periodically and burn them (making sure you stand upwind of the fire),since they do not decompose readily, taking several years to break down.

The new Sambucus - 'Black Lace' will love that situation and you can prune it as much as you want. Beautiful, dissected purple foliage - almost like a Japanese maple.

I have a Clethra alnifolia (sweet pepperbush) in a similar position in acid soil. It flowers late for a bush, in August, is scented and attracts butterflies.