I would go with the NEC 22" CRT Flat Screen MultiSync FE2111SB, it's supposed to be the best out now for high end machines.
A few years ago the Sony FD Series monitors were pretty much the best you could buy. I have a GDM-F500R that is a 21" flatscreen with 0.22mm dot pitch and very good convergence and focus out to the corners. It has served me well.
But... That was a few years ago...