Having read all the IGN head to head articles from the 6th gen consoles, its allways the PC coming on top regarding graphics and sound, with the Xbox being the best of the consoles (GC/PS2).
On some games like prince of persia the PS2 had additional heat wave effect the other consoles didnt have, yet the conclusion was that the Xbox and GC versions (and PC) where having much better graphics thanks to higher resolutions, higher res textures, more stable framerates, filtering etc. Often PS2 versions of games had problems with 'shimmering', lower fps and things like lighting etc. Load times where longest on PS2 aswell.
All of this was for all of the head to head from IGN, all titles i could find, same conclusions from gamespot and other review sites. PS2 was allways the worst of the bunch, pc getting better versions. This is including reviews with Geforce 2 cards (dont know what model).
What suprised me was that PS2 often had so much worse audio quality compared to xbox and sometimes even GC.
As a side note, for most games the PS2 was the lead platform according to reviewers.
Myself having xbox, ps2, obviously pc (and GC), with the games i could do comparisons against pc versions of the time, pc was quit ahead. PS2 certainly had some additional effects but as a whole the pc would output the better looking picture, guess higher res, filtering and higher res textures do their job.
Offcourse then we have exclusives and games that were maxing the PS2 more. For those games its harder to compare to the PC since there wasnt many games on that platform that where optimized for a GF2 and P3. What i do know is that Black is one of the most taxing PS2 games using its hardware, ran both the xbox and PS2 version, xbox seems to be 60fps vs PS2 30fps, at higher resolution, colors, filtering and again sounds so much better?
Black is having a motion blur when reloading, how good this MB is i dont know, but theres youtube videos on it, im no expert, just seeing the irritating blur
Now i do know xbox has a GF3 with extra vertex shader, so how it would look on a GF2 64MB, athlon 1ghz with 256mb ram, dont know, but certainly better then PS2 in most regards if optimized, since xbox's only advantage over that pc would be GPU, the 2000 pc having a much faster CPU, much more ram, and dedicated ram to the GPU certainly makes up for some things.
BF1942/vietnam with its 64 player maps certainly wouldnt run in its original form on PS2 is my thought....
Also, seeing as the GC almost always came ahead in multiplatform games, and having in most peoples eyes the better looking exclusives then PS2 (rouge squadron), with the GC having a <500mhz cpu and gpu comparable to something DX7 level, i guess that pc would be more capable.