20" Apple Cinema Display £399
23" Apple Cinema Display £599
30" Apple Cinema Display £1199
See here....
http://store.apple.com/uk/product/M9...ys&mco=MTI1NzI
The larger the monitor the more powerful graphics card needs to be to drive it, for instance the 30" ACD needs a dual DVI card.
I noticed the refresh rate is lower on my 23" ACD than my beloved 17" Sony Trinitron.