ATI HD 5xxx and 6xxx cards do technically support 3D, but there are no drivers for that feature. The 3D drivers will not be developed by AMD/ATI itself, instead they have decided to make it open source so that the development community can develop the drivers; kinda like Linux.
You have two options.
1. Go for a e-IPS monitor which generally offers better colors and viewing angles at the expense of slightly higher response times of 8m vs. 2ms/5ms, such as the Dell U2311w. Still usable for gaming and well suited for photo editing and movies due to better colors.
2. Go for a 120Hz monitor that is 3D capable. Based on what I've read gamers seem benefit even if they do not use the 3D feature. The 120Hz refresh times generally means games look a lot smoother than normal 60Hz monitors.
Here's an example of a 120Hz monitor. I don't really know what the top 3 120Hz monitors are though.
TN film (Twisted Nematic + Film) panels where the first panels to be used and are still widely implemented in many TFT’s today, especially mid to low end screens. This is due to the low manufacturing costs of TN panels. Traditionally they were not always very good at displaying blacks, but modern TN Film panels are actually very good in this regard. In fact many can compete with even VA matrices. There is also a problem with pixels dying and becoming a bright colour rather than just completely going out (black). The main issue with TN Film panels is that they have restrictive viewing angles of up to a realistic range of about 140 horizontally. Vertical viewing angles are very poor generally and suffer from a characteristic blackening of the image as you look from below. TN film panel traditionally offer the fastest pixel response times, and with the implementation of RTC / overdrive technologies, the grey to grey transitions have become even faster. Today, TN Film panels are used in the majority of gamer-orientated screens and are often used to break into new screen sizes, offering a cost effective way to provide larger screens without increasing the price too much.
IPS (In Plane Switching) was introduced to try and improve on some of the drawbacks of TN Film. It was developed by Hitachi and was dubbed “super TFT”. They improved on viewing angles up to about 170H. This was done by controlling liquid crystal alignment slightly differently, but unfortunately, can affect response rate of the pixels. As such they are not as good for gaming as TN panels. IPS panels were later developed into Super-IPS (S-IPS) panels by their main manufaturer now, LG.Display (formerly LG.Philips). Production costs were lowered which has meant they have become more widely used. S-IPS offer perhaps the most accurate colour reproduction available in the TFT panel market, and the widest viewing angles as well. They are also free of the off-centre cotnrast shift which is evident on VA matrices, and as such are commonly the choice of graphics and colour professional displays. Response times were traditionally behind those of TN Film and VA panel variants, but modern IPS panels using response time compensation (RTC) including the new generation of Horizontal IPS (H-IPS), Enhanced S-IPS and Advanced Super IPS (AS-IPS) panels can offer responsiveness to rival both.
TN panels generally have 2ms/5ms response time, e-IPS panels are slower at 8ms so will generally see more ghosting effects.
All IPS panels will have better viewing angles than a TN panel.
I'm not familiar with the BenQ monitor other than it uses a TN panel, but it is in your budget. If your primary concern is gaming and you don't mind spending the extra $$, then look into some 120Hz monitors. If you don't like what you saw in the above videos regarding the TN panel monitors, then consider the Dell U2311h which is a very good all purpose monitor; just keep in mind that you may see slightly more ghosting since your Samsung SyncMaster 2232GW is advertised as a 2ms response time monitor.