I hope the U2312HM is good, just recommended it to a boss at work, it will arrive in the new year so I can let you know what it's like.
I've just ordered a Samsung S24A350H off the back of some strong recommendations. Seen them in the flesh too in shops and they look the part. Will get mind Saturday so will update you then as to what I think.
You can go for Samsung SyncMaster 2493HM 24 inch LCD Monitor which is a nice one. It is one of the best monitors available at present. You can check its specifications and decide yourself.
Just ordered the Samsung S24A350H. Got it pretty cheap, should be a good monitor for the price.