The Dell's res is too high if you play games, as you are going to have to run it at that res all the time or have the monitor resize it.
I would go for the viewsonic.
Anyone else seen better LCD monitors or TV's around the same price and size range? Keep in mind the Dell monitor has the picture by picture feature, where you can plug in a Cable box or Xbox while on the computer at the same time. I just want people's opinions because I haven't seen any of these monitors in person only through the internet.