If your looking at 24'' but dont want to pay quite as much as the dell, you could also consider the hp zr24w. It has more or less the same specs as the U2410, but isnt wide-gamut and, more importantly, only costs around $400.
Another possibility to consider is a monitor with a VA panel of some type, they are still better for image quality than TN but not as expensive as an IPS panel. I just bought an hp lp2465 refurbished for $200, and it serves my light gaming needs well while still being a very buisness-oriented monitor. I think amazon is out of stock by now, but if your willing to go the ebay route $200 is certainly cheaper than $400 or $550, for a (fairly) comparable product. (side note on the lp2465 - its been reported to have fairly high input lag, but, at least in the one I got, it still has less than my laptop screen does, and, again at least in my case, it isnt noticeable while playing fast-paced games)