I would second either a Dell U2x11 series or a Apple Cinema Display. In terms of color reproduction quality, those two are absolutely fantastic. There are some high end HP and NEC branded monitors that compete nicely too.
Purists say that CRT screens are still absolutely the best color reproducing screens. However, flat panels are starting to approach that color quality. When looking for a LCD monitor for your use, make sure to stay away from a TN screen. Their color is not that great.