I kinda and kinda don't have the money for it. You see I'm a full time college student and the person who brings home the bacon is my wife. I could just tell her that the 27in monitor will do me good for a very long time and she'll be ok with it, but if I can't even tell a difference from the 24 and 27 then I don't want to waste money.
I would always go for the 24" - they are exactly the same resolution, so all you are gaining is the screen size. The one exception would be if the computer will be used for movies all the time, or something similar where screen size matters more than resolution. The 24" will look sharper though, due to the smaller pixel pitch.
In this case the bigger screen has the same pixel count as the smaller screen, you will be looking at a poorer quality image with bigger more visible pixels negating the effect of the anti-aliasing power from your graphics cards! Sure you can sit further back so as to not notice these, but then you lose all the benefit of a bigger screen. (Effective screen size reduces with increasing distance fromt he screen)
For watching movies a bigger screen is better for playing most games I prefer a higher quality image over a bigger screen,(despite having a 120" screen hooked up to the pc in the living room) Car driving games would be an exception to this rule for me, There I place view filling and realistic seating and controls at a premium as long as I can get "acceptable" image quality.
All that said I am something of a perfectionist when it comes to image quality, and many people love their "big" screens. Perhaps what you need to do is take a look at the screens and see what suits you. Whatever you get if you are happy with it you havent got it wrong!
27" is to 24" is what 22" is to 20". Now how many people here can say they honestly prefer a 20" over a 22"?
Go to a best buy and look at the difference. 3" is alot of extra surface area, the size will likely bring a smile onto your face even as the rest of the computer ages. I always recommend going no-holds-barred for monitors because it has such a dramatic affect on consumer satisfaction.
Actually I brought a 20" over a 22" for EXACTLY that reason, (samsung 2032bw over 2243) I still think this screen is utter pants compared to a 19" (17" viewable) 2048x1536 CRT, but its definetely less irritating than the 22".
I pay out for high end graphics cards to try to get the best image I can out of the computer whats the point in paying for something with great AA abilities and then playing it on a screen with gonzo sized pixels... Waste of GPU power.
I have a BIG screen, But I still prefer image quality over image size for most games. This becomes quite important when playing games with lots of "stat" bars to keep an eye on, big screens up close mean you start to have to look around at different areas to keep an eye on the stats missing out on some of the action (one very good reason I dont bother playing mmorpg's on a BIG screen)
Why dont you go on Newegg and get a better monitor for way less. You are paying ridiculous amounts of money for a dell. You can get one of those samsung TOC 24" monitors for under 500, and they have better specs. I saw 6ms response time. I have a 5, but I am looking for one with 2. 5 seems good and i think thats what that TOC one is. Plus, it would double as a TV because it has TV hookups.
If you dont need it as a tv, or if you have a cable box, then just get the one without a tuner, because its 100 bucks cheaper. It has an hdmi one the back and it would be a shame to watch SD on that screen.