A few ideas:
1) Euonymus fortunei cultivars make very attractive, evergreen lows shrubs or groundcover, e.g. "Emerald & Gold" (green with yellow variegation that turns pinkish in winter) or "Emerald Gaiety" (green and white). "Harlequin" is another good one - the small green leaves are heavily sprinkled with white - it really sparkles in a dark corner. They will also grow up against walls to a height of several feet. I have lots of them in the very shady borders surrounding my patio and they seem very happy.
2) There are other evergreen Euonymus varieties, such as Euonymus japonica, with gold variegation, that grow much taller.
3) Hellebores are fairly evergreen perennials that do well in shade. Most have beautiful flowers from winter into spring. Small plants do take a long time to establish, though.
4) (and this might sound a bit daft...) you could do put in a few obelisks planted with variegated ivies, to introduce a bit of height and... er, daftness...
5) Primula are good for ground cover, with bright flowers sporadically from autumn through to their main flowering period in late winter/early spring (sorry - I know you were asking for shrubs, not perennials!)
6) Of course, if you have acidic soil, you could add a camellia or two. The leaves are maybe a bit dull, although glossy and light-reflecting, but the flowers in spring are worth it, and being shaded from morning sun is ideal for it (the buds can be damaged if they are frozen and then thaw too quickly).
7) The tree heath, Eric arborea, gets gets to about 6 feet (and can tolerate a bit of lime). "Albert's Gold" has allegedly greeny-gold foliage, but mine just looks green.
Most of these won't like dry shade or impoverished soil, so dig in as much organic matter as you can before planting.