I have planned to replace my blue&white G3 by a cube 500 with a new monitor. I am dreaming of the 15" flat panel

BUT I am not sure that this would be the best choice. Maybe you can help me ? My activities are (1) video editing (iMovie/Final Cut), (2)internet surfing (3)games (4)...
1) Is the flat-panel viewable area as big as the one on the 17" ?
2) I saw on a Powerbook that some colors (light grey i.e.) are just not viewable. Will it be the same on a 15" ?
3) What about playing games with that monitor ? (colors, nuances, ...)
4) Is the 15" reliable ? I read many comments on cnet that says there are often technical problems after a few months ... ?
Thanks for your comments !!