An interesting survey that Valve are conducting at the moment. I expect it mainly consists of HL gaming rigs, therefore represents a rather specific market segment, but the results are interesting nevertheless:
http://www.steampowered.com/status/survey.html
They’ve screwed up the RAM and processor features questions, network speed is obviously going to be biased towards broadband, and you have to take HL technology into account when looking at screen width etc, but here are some interesting numbers so far:
[]60% of surveyed CPUs are between 1.5 and 2.7GHz.
[]82% of users are running XP.
[]The CPU field is split 50:50 between AMD and Intel.
[]99.83% of machines are single-processor.
[*]60% of respondents prefer OpenGL; 32% prefer Direct3D.