In my opinion fancy video cards are only "needed" for games with high frame rates. Since you don't need to refresh the screen 100 times per second when using Photoshot or Lightroom, any old card will do just fine. I run Photoshop on 2 PCs - one has a pair of nVidia 8800 GTX cards that originally cost 850 Euro EACH - and the other has a pretty entry level card ...
... and there's no difference in Photoshop performance.
What DOES make the biggest difference is shear horsepower (I use a CPU with 8 logical cores) and as much RAM as you can fit in the machine (I use 12GB).
Than you Colin
I think I will go to the iMac 27" with 2.8 HGz and 18 SDRAM.
My wife takes my still good working iMac 23" and I receive from her the Lacie 19" to work as second monitor.
Or, I work with the 27" and the Wacom Cintiq I have been using since last year.
Thank you Colin. Have a nice week end
Looks good Antonio. Still not a PC of course, but I think you've gone for the next best thing