Intel. Works very, very closely closely with Linux devs, and AFAIK releases full specs. Given that Intel are expanding well beyond their CPU origins (Intel NICs are among the best I've worked with, graphics chipsets are pretty good, others generally work well), this is cool stuff. In the case of my most recent Thinkpad purchase (May 2011), it took updating to the latest kernel on Debian 3-4 months after purchase to iron out all the bugs (hangs/restarts), but since then it's been golden.
AMD aren't far behind, and since they picked up ATI (Radeon graphics), the Radeon support is also quite good.
S3 were making some noises about being very solidly behind Linux as of 4-5 years ago (bought me a round of drinks at a Linux conference, so their support is demonstrably liquid, if not solid). I've had pretty good experience with older Matrox chipsets, no idea where they are now.
My experience is largely desktop, server, and some light video viewing. Hard-core gamers may have other complaints, but my understanding is that you'll probably end up on Windows or a dedicated gaming platform in that case anyway.
AMD aren't far behind, and since they picked up ATI (Radeon graphics), the Radeon support is also quite good.
S3 were making some noises about being very solidly behind Linux as of 4-5 years ago (bought me a round of drinks at a Linux conference, so their support is demonstrably liquid, if not solid). I've had pretty good experience with older Matrox chipsets, no idea where they are now.
My experience is largely desktop, server, and some light video viewing. Hard-core gamers may have other complaints, but my understanding is that you'll probably end up on Windows or a dedicated gaming platform in that case anyway.