Graphics card advice for GIS / CAD work

[gis_mapper]

I'm putting together a new system for GIS/CAD processing and also use some raster images to 200 Meg in size.

My motherboard is the MSI K8N Diamond Plus with an Opetron 165 CPU, 4 Meg RAM and Coolmaster 550 W PSU.

What graphics card would people suggest for this setup? Many thanks.

 

[gis_mapper]

I should also add that I'm running two ACER AL1913 19" monitors.