I have been thinking about getting a widescreen monitor but I don't know what it will do when I play Call of Duty (any version). Will I lose anything top and bottom or will I have dark areas on the sides or will it simply be perfect.
In short, it depends on the resolution. If you set the game to the monitor's native resolution, then it will be perfect (no dark areas). But if you set a resolution in the game lower that your screen's resolution, you may get dark areas. If you're getting a widescreen monitor, you should have a pretty darn good graphic card that can handle that high resolution.
A GeForce® 9800 GT (1GB) should handle that I would imagine, along w/4GB of Dedicated Ram. I usually set it to 1024x768 but of course that is with a regular monitor. I haven't yet gotten the hang of the dimensions of wide screens yet. Do you know of a decent monitor that doesn't cost more than $125 but is @ least 1000x1?
Yes, I would imagine that a 9800 GT is very well capable of handling Call of Duty at high res with highest settings.