Somehow I always got a good impression of Matrox cards.
The old millennium and millennium II are solid cards with
very good support on X and their new MGA100-400s
should be the same, but I have no experience.  You might
also want to look into 3dfx Voodoo 2 and 3 based
cards.  My experience with those is that support is generally
good, maybe even 3D supports.  I have a Banshee but
I let my little sister uses it to play games so have no
real experience with X on it.  Lastly, nVidia's TNT
chips are fairly popular and support for those should
be reasonable.  I have a TNT2 card, but I only run
it with Windows and BeOS.  Unfortunately I believe
2D support is as much as you can get with them unless
you uses M$ windows.  Et6000(ancient) based cards
is also a decent card.  I am actually using one on a
Linux server and I am quite happy with it.
Finally, I believe you can't go wrong with Matrox cards.

Also, cards based on the S3 Trio, Savage 3D, and savage 4
chips should be well supported.  My brother actually worked
on the original version for Savage and source code is available.
S3 has taken it over and rewritten it.  It's mainly targeted for
Linux, but people have reported they compiled it for
BSDs.

If you don't require 3D, you can actually get a decent card
that's well supported pretty cheap.

As for ATI cards, I somehow just got a really bad feeling in my
stomach whenever I hear that name.  The main reason is that
they have all these zillions of different cards with catchy names
and I can never figure out which is which, what chip they use and if
it's a newer revision, and if there is compatibility problems.  So
personally I avoid them at all costs.  They made decent gfx
chips, just the marketing scams they have doesn't work well for me.
I actually have some ATIs and Number 9 cards lying around
that I forget what I have used for.

Jon Lindgren wrote:

> This is most likely a well worn question, but I must ask again:
>
> Has anyone had any excellent experiences with PCI cards for X?  Perhaps
> any which I should actively avoid?  I need to bring up a new workspace, so
> I figured I'd shell out the bucks (hey, it's the holidays :-/ and buy a
> good card.
>
> I figured I'd eventaully end up with an ATI card, but if anyone wanted to
> persuade me to another, I'd certainly be appreciative.
>
> Thanks,
>
> -Jon Lindgren
>  "Xyzzy!  You're a duck!"
>  jlindgren@espus.com, yubyub@yubyub.net