It depends on your budget 🙂
Samsung T220 22" good and quite cheap – ~£240
Lenovo 22" L220X – £293
Samsung T245 – £400
Dell UltraSharp 2408WFP Black 24" – ~£420
If you have wide pockets then take a look at professional LCDs
NEC MultiSync LCD2190UXi-BK 21.3" – £603
Basically NEC UX and SpectraView series are good when working with colors.
EIZO ColorEdge CG222W 22" – £800 (?)
Going up you can look at something for LaCie or if you are insane – Barco (although sizes start from 30").
Don’t forget to check what type of matrix there is – S-IPS is far better for design/photography works than TN matrix.
If that would be me I would choose one of two top ones (Samsung or Lenovo)