Buxus semperivens might be OK. Taxus baccata is another. Both are evergreen
and relatively slow growing so won't give you the problems that can come with X
Cupressocyparis leylandii and other conifers commonly used for hedging. An
advantage with Taxus baccata (Yew) is that it has red berries, so has some
aditional colour for at least some of the year, and if it ever does get too
large, can be cut back as hard as you like (within reason) and will grow back
from mature wood. I've seen them left to grow into mature trees only to be cut
back to a stunp, then happily grow again from the trunk and form a hedge.
Conifers are something to be avoided in my opinion, and I think that's likely
to be the concensus when most gardeners are asked.

I hope this is helpful, but if you don't like my suggestions feel free to come
back with any further thoughts and I'll see what else I can find for you.

Dave.