The Dell Ultra Sharps come with IPS panels which give better and more accurate colours, better off angle viewing, just better all around panels compared to TN panels, except for response times. You pay for it though but sometimes they come up on Days of Deals for reasonable prices. The 23" one was on a few days ago.
If you are into it, the 30" USharp is on sale right now for $999.
I got the ST2410 which is a TN panel and it suits my needs well.
Here's a list of current Dell monitors on sale. Maybe check the Days of Deals bargains which has 6 days left.
http://accessories.dell.com/sna/sna.aspx?c=ca&cs=cadhs1&l=en&s=dhs&~topic=hotdeals _monitors