What about escallonia? It's fast growing and can be clipped to keep it neat. If you prune it at the right time you will get flowers too. The bees like it!

You can grow hydrangeas in a row, but they don't make a very dense hedge, and it needs to be pretty wide so you'd lose lots of front garden space. If you kept hacking them back to keep them smaller you'd lose all the flowers and leaves.

The "classic hedge" plants are classics for a reason - they're suited to hedging. They take clipping well and can be grown in a thinnish line so each plant is wide but not thick. How about a beech hedge? They keep their leaves (brown, not green) all winter, so are good for privacy, but have more variety than evergreens.

And there's good old privet. Not exciting, but useful and easy, and our wood pigeons love eating the shoots. Do I care? They're helping prune it, in their way.

Lonicera nitida is another reliable hedge shrub with small leaves and dense growth.

The sort of "informal hedge" you are thinking of takes up more space than the formal sort.

Beatti, beech hedges are great but they do get wide as they age, even if they are pruned hard (ours has anyway - it is just coming up to 20 and is almost 3 feet thick, and I think it might look out of proportion if its only going to be 6 feet long, especially as it has quite large leaves.

The lonicera nitida can be a bit boring left to grow on its own, but well clipped it can look fantastic and makes a good foil for any flowers you might want in front of it - I would go for the gold leaved one, as the plain green can look very dark. You might find that its tiny leaves will be more in proportion to the length you will have.I couldn't think of any wild life ones that don't have thorns!

Another option is Berberis darwinii - evergreen, admittedly prickly, but not thorny, orange flowers in spring, blue black berries later, can be clipped twice a year. Ultimate height 8 feet if you don't cut it though.

One drawback with lonicera nitida is that it is very fast growing. To keep it looking tidy, it will need trimming every couple of months in the growing season. Another possibility is one of the smaller forms of viburnum tinus with the added bonus of flowers right the way through the winter; they can be cut back if necessary in spring

Lonicera Baggesons gold makes a much more attractive alternative to basic green lonicera nitida. It takes trimming well ,is evergreen and the new growth in spring is a fantastic gold colour

http://www.lejardindesophie.net/jardinautes/sophie/phoplantes/l/lonicnitidbagg.jpg

I know you say you don't want spikes, by which I guess you mean thorns as in pyracanta but there are some lovely variegated hollies which are not too sharp and there is at least one hilly with no spikes at all.

...or Potentilla fruiticosa makes an informal hedge and has colourful flowers all summer.

I saw an attractive hedge of small leaved Euonymus round a supermarket car park today. It wasn't as tall as you specify, but might get there, given time.

I was wondering about Euonymus Silver Queen - that'd get more than big enough eventually, but Euonymus do tend to prefer a bit of shade rather than full sun, and aren't great in cold winds.