Hmmm..Choice is up to you really. If you want either a PVA/MVA panel or a IPS...
The Dell's use a S-PVA panel....The Samsung uses a S-PVA as well....While the BenQ uses a MVA...
MVA/PVA panels have the highest contrast ratio and best blacks..But details in the black are lost. This is called "Crushed Blacks" which is the term for it. Also PVA/MVA panels have the highest input lag and response time of TFT technology. If you take gaming very seriously this might mess with you. But it all depends upon the person...Some people can see ghosting and some people can not on the same monitor...Every person is different. I was and somewhat still am a dedicated Counter Strike player who has played many leagues..I also play a LOT of different kind of games...For me if I had to go TFT I'd nab a IPS panel. They have the best color accuracy as well as maintaining the details in darker areas. The downside is their brightness contrast is not as high as PVA/MVA...but the color accuracy, details, input/response time makes up for that. So the choice is up to you...
I have very quick reflexes and my eyes can notice quite a bit. I can see pixelation and defects quite easily compared to others who barely notice them...So it all really depends on how your eyes react.
For me I'd go IPS...I decided to skip TFT panels since I'm waiting for FED in 2009...Basically think CRT in flat panel form...all the benefits of CRT in the size of a LCD. LCD's have lots of problems which is unfortunate they replaced CRT's....CRT's are still superior to LCD's in many aspects. But like all technology it has some weaknesses which LCD's have favor...but vice versa as well. LCD's can never get near the level of blacks and detail as CRT's. LCD's also have a delay which gets the video a few frames behind what is actually going on. CRT's have delay also but is so faint it's not noticeable unlike lcd's...
Considering you are willing to spend 700...Why not add another 250-299 and get a 26 inch IPS?...You can get the Planar 26 inch which has a H-IPS panel. It uses the same panel in the Nec2690WUXI which retails for 1700...Although the firmware on the PLanar is no where near the quality of the NEC...so it has problems but for the price and size it's damn good. It also has a 5 ms respose time with 1 frame of lag. Quite a nice deal for a IPS panel. If I had to nab a LCD for myself I'd grab a Nec 2690WUXI...They go for 1700. The Nec 2490WUXI goes for 1500. But considering the price point of the Planar it's a steal.
If ghosting and whatnot doesn't effect you much then by all means a any of those monitors you mentioned will do you fine. Tomshardware doesn't have a real active display community. If you really want to learn a lot about LCD's and read ACCURATE reviews about the products head over to the Hard forum's display section..It's VERY active.
http://www.hardforum.com/forumdisplay.php?f=78
I was gonna nab myself a Nec 2690WUXI but I've decided to nab a Sony FW900 Wide screen 24" trinitron CRT...The downsides of LCD are just too high for me...I'mma just nab myself this top of the line CRT till 2009's FED technology...This CRT goes for around 200-350 on Ebay used...They stopped making it in 2003 thanks to flatpanels taking dominance..They retailed for 2,300. You can get them refurbished as well with a 1 year warranty from a company for 700 as well...that's where I'm planning to get this sucker.
But yea...check out that forum. They'll be tons of reviews..You can also make a thread and ask for thoughts and I'm sure people will help youout. If you have any detailed questions to ask go for it. I'll help to the best of my ability. What will this monitor be used for? There is no perfect LCD out there. They all have their faults. So researching into TFT technology and understanding the products is the best way to get a monitor that suits your needs. Each have strong points and weakpoints...So what is going to be the full use of this monitor?..Just gaming?...any video work?...watching movies?...photography?...