Adding to Susie's as another Brit that can recommend

For the yukky deep hacking coughs that make your head swim
1) Boots or Superdrug " Pholcodeine Linctus" approx £1.40 for a bottle
make sure you get the sweetened version, the un is vile
2) For a non-narcotic one try "Vegetable Cough Remover" from Holland & Barratt or other healthfood stores
I think it's made by herbal company "Potters"
3) Corvonia - V.V. Strong, but helps a lot (lots of people get addicted to the stuff though, so watch it

The Pholcodeine Linctus works brilliantly though - you need to ask for it at the pharmacy counter.
For tickly, dry throats that wont go away but don't make you cough horribly, Boots Blackcurrant & Glycerine, (approx £1.20) tastes like syrupy ribena and really coats the throat.
I don't think anything we have here, apart from the Phocodeine linctus is anywhere near as good as the tiny sample size "narcotic cough medicine" that a US Dr gave me when I had a really bad cough/bronchitis when I had no medical insurance over there- it was vivid orange, tasted just like a nice flat orangeade and I had the best week of sleep of my whole life

Sheril.
Forgot to add- Hubby (from Connecticut) moans every year that we have nothing as good as that lethal potion known as "Nyquil" - we used to have "Night Nurse", but not sure if we still do and that was dark green witches brew!