The 9500GT is a good choice if your going to get an NVIDIA card with good
graphics support:
https://www.thinkpenguin.com/gnu-linux/geforce-9500gt-1gb-pci-express-20-video-card-gnulinux
It is well supported by the nouveau project and the nouveau driver is now in
the mainline kernel so pretty much any free distribution will work out of the
box now.
Most other readily available NVIDIA graphics cards are not good choices at
this time.
The best supported graphics on GNU/Linux is Intel.
Other than that stick to Atheros for wireless PCIe/PCI cards:
https://www.thinkpenguin.com/catalog/wireless-networking-gnulinux
There are other possible issues you can run into building a free software
friendly system although these are the primary issues you can avoid easily.
ThinkPenguin (I'm the CEO) can also sell you a motherboard if you inquire.
There are three models we stock and use specifically for there good support
for Trisquel and GNU/Linux in general.
Cases, power supplies, CPUs, etc aren't much of an issues. The only thing
with CPUs is I'd advise you to avoid the ones which support digital
restrictions.
You can look up models on Intel's web site:
In the table it should list it as:
Intel® Trusted Execution Technology No
