Lovin' my Dell screen
I got a sweet 20" widescreen LCD from Dell about a year ago, and I absolutely adore this screen!! If I was a millionaire (+/- a "little") I'd get the Apple one, but as a student, the design and 'coolness' factor doesn't justify the double price IN MY OPINION.
(and I've moved my Dell screen around a bunch, inc. to new apt, the plastic is really sturdy and hard I think, I can tilt and rotate the screen in all various angles, no problems at all. I don't have a TV, so I'll move the screen to the living room and we'll sit in the couch and watch it. No one's complained about the viewing angle either. The extra USB ports on the side are nice for connecting your cell phone, camera, USB stick etc).
Maybe my eyes aren't as "fine-tuned" as everyone else's, but screen-wise I couldn't tell a difference between Dell and ACDs. Maybe the price blinded me.
Apple's going for a differentiated strategy where you pay for the

logo and design (something gotta justify the higher price) whereas Dell is more of a mixture of cost-leadership/differentiated side.
I'd personally go for Dell, and instead bump up the size if you feel like spending the money.