The free (as in freedom) ati driver isn't that bad, especially if you have a radeon <= 9600. There is no free driver for nvidia cards. Intel release their drivers under a free license, for some of the cards.
So if you wanna have decent free drivers available, ati isn't so bad. Plus fglrx and the nvidia driver are of questionable legality too
Plus, a lot of people reckon AMD will release the code of the ATi drivers, if they do we'll have a kick ass free DRI driver, stable with all ATi/AMD cards, after a few months.
my radeon 9600 is running well, with the free driver. I've never setup fglrx
Yes if you're stuck in the stoneage with old cards but good luck getting a x1900xtx or a x1950xt running with the free radeon drivers. Pre x1800xt cards ain't worth shit for todays high end gaming and heavy 3d work. If you want to keep up with the game and 3d work development you have to upgrade frequently.
The rumour about ATI releasing free drivers is just BS. Either way it would just be a functional driver as they said; no 3d, xgl, aiglx, high performance etc. An ATI/AMD rep recently said openly that there are too many patented optimizations in the driver to make it open source. He also specifically said "It's never gonna happen".
And yes there is a free driver for nVidia (nv) however I don't think it provides accelerated 3d but who gives a rats ass when "nvidia" works perfectly. I got two computers with nVidia who never have problems except one crash because of high Xorg cpu usage.
And did I forget to say that my computer frequently randomly locks up when I'm GNU/Linux even with the "radeon" driver while Windows XP is rock stable.
ATI makes very good hardware (except the high power usage) but the software blows just like in Windows.