hehehe, no dude.
Intel makes pentium central processing units (CPU's). Nvidia makes graphics processing units (GPU's.. and well, they design the GPU's and graphics cards, they don't actually make them). There's a diff.
Intel and Nvidia ain't even working on the same systems for consoles! Right now Intel and ATI are making the $box360, and Sony n' such and Nvidia are making he PS3.
The closest partnership they have is with companies like HP that package Intel cpus and nvidia graphics cards with their computers.
So there ya go, settled.
Now, an ATI Radeon 9800 pro is a plenty fine graphicscard. It can crank out some satisfying visuals. Not the highest-rez, but fine none-the-less. Plus their Canadian, so we must support our fellow brethren eh?
You wanted best-bang-for-your-buck? that ATI Radeon 9800 Pro is probably one of the best marketed cards ever. Heck, it's the most sold videocard made. It's outsold the Geforce 2 series, AND the geforce 4 MX440 (how it sold soo many? HP's n' such, their cheap computers). So yeah, a retail vidcard pwning one that is placed in many brand name computers? that definately shows a sign of strength.
Now, for the Valve hardware survey, check this:
ATI Radeon 9800 Series 121,579 10.37 %
ATI Radeon 9600 Series 117,084 9.99 %
NVidia GeForce4 MX Series 99,358 8.47 %
NVidia GeForce FX 5200 Series 97,734 8.34 %
as you can see, lots of ati users on the source engine.
now... a little more down the list...
NVidia GeForce 6800 11,542 0.98 %
NVidia GeForce 6800 Ultra 5,543 0.47 %
as you can see, not many nvidia users (well, that participated in the survey at least). Now this survey is a little old, this was maybe a couple weeks after the release of HL2. So the figures are probably different, probably more 6800 users and at the time the 6600gt wasn't released. So I'm sure the number of 6600gt users on hl2 have gone up. If it'll be more popular than the 9800 pro? we'll see in time.