GHD are absolutely great, they are what most of the salons here in the UK use, I have a pair of my own and they are the best.
You can get them in differing sizes to suit your hair style / type.
I found that searching the Internet for good deals was worthwhile as I managed to get the straighteners I wanted with a bag, styling products and hair clips for less than I could get them direct from GHD. (GDH = Good hair day).
I bought mine from SalonLines - recommend you try here.
www.salonlines.co.uk