Time to crunch your piggy bank...........
Thanks for the helpful reply - interesting stuff. However, I don't think this answers my central point - about auto-detection.
I have five networked PCs which I use for various purposes including web design, media centre etc. I run Debian stable for my "production machine", Mythbuntu or Mythdora for my media centre, SimplyMepis for my wife's PC, Win XP for testing websites with IE, and a test box for just trying things out.
Up to about a 1-2 years ago, I found it normal to have to download and manually install proprietary nvidia drivers. However, more recently, most distros seem to be able to auto-detect the video card and offer to install the correct drivers.
I have a Geforce GT8500, a GT 440, a G210 and even a (fanless) FX5200 for my media centre. Old though they are, they run happily with nvidia drivers and do more or less what I need of them. I don 't need the latest all-singing/dancing cards - sometimes all that happens is there isn't yet a Linux driver for them! I haven't had to do more than click "install" for drivers for ages on any of these cards or distros I have tried.
I last used PCLOS for about a year up until last year. It was great through the early versions of KDE4, but then it began to lose sound and the desktop settings. Now I try PCLOS again, just to see how it is getting along and the best it can do is install VESA drivers for the nvidia 400 series card. As far as I can see, PCC doesn't recognise the card or offer to install the nvidia drivers. I have dkms-nvidia-current installed but can even find nvidia-settings in the repos - I needed this to help set up TwinView across two monitors. Linux is supposed to be supreme at getting things to work on moderate/ageing hardware - but this doesn't look like it. I do know how to manually install the drivers and even how to write my own xorg.conf from scratch, but don't see why I should have to in this day and age - just to try out a distro.
Off-topic but relevant:
BTW: during install PCLOS did pick up Mepis on another partition and added it to the boot menu. But clicking on it during boot just produces error messages and it won't boot. Since all my wife's stuff is on the Mepis partition she was not best please to be unable to boot to her own distro. I had to download a copy of Mepis 11, burn a live DVD, boot to it, and use their excellent "Repair Grub" facility to restore a workable boot menu. Not very reassuring.
Anyway - I am persevering and will have another play/read more about PCLOS and see if/where I might have gone wrong.
But I'm afraid that buying a new video card isn't "on the menu"