The Dell 2408 demonstrated outstanding contrast ratio and black level values for a 24” monitor. Same or close to the Eizo HD2441W (according to a popular test magazine).
The contrast ratio is stable within the whole range of brightness.
A technical minimum (monitor brightness 0%, video adapter brightness 0%) at 50% contrast is:
White – 76 cd/m2
Black – 0.11 cd/m2
Contrast ratio – 690:1

Regarding “Dynamic contrast ratio”. This is something like “Dynamic blood pressure” – systolic BP of my grandmother (160/80) measured against diastolic BP of my grandfather (110/60). So “dynamic” blood pressure of this family is 160/60.
Dynamic contrast mode makes the screen darker when a dark scene is displayed, and brighter when a bright scene is displayed. As these images are shown separately (at a different time), there is no sense in talking about “contrast ratio”. “Dynamic” is just an elegant word. Sounds good for commercials. A trick to deceive an ignorant buyer. Don’t pay attention to that.
A sort of dynamic mode is implemented in the reference NEC 2490 too. But it works in opposite way. The monitor drops brightness when a bright scene appears – to reduce eye strain.

During the process of calibration (at the white of about 140cd/m2) measured contrast ratio plays around 1300:1 – superb!