For those curious about buying DS3 even partially for DS1 & DS2, here's my findings so far.
They work on Win7 x64. That being said, I'm having a devil of a time with lag. This is gameplay lag as well as cursor lag. The cursor is noticeably slow and the camera is jerky and is mostly noticeable with the edge scrolling, but also during movement as well. I've got a 2.4ghz core2duo with an HD6850.
I've tried compatibility modes and CPU affinity with no luck. I'm going to force vsync off when I get home tonight and see what that does, as I'm quite certain it is on by default in the game, with no way to disable it. I've seen this kind of cursor lag before in other games when vsync is enabled (Dark Messiah springs to mind). In addition, I read somewhere that people had some success setting the compatibility mode to Vista, though it seems odd. I'll try it if vsync off fails, as it's more or less unplayable at the moment.
From what I can tell, mods also don't work. I've tried the far zoom mod, the large text mod and the far fog mod, all without any noticeable differences. If anyone has gotten these working, please let me know how. I've not tried anything beyond just sticking them in the resources folder.
I've also tried the various widescreen fixes, but I can't really see why they're necessary - just setting the resolution in the .ini file seems to work fine. I've read that without the widescreen mod fixes, the resolution is vert- as opposed to horiz+, but I really don't care that much to mess with it.
The farther fog, farther zoom and larger text mods would be very nice though. Has anyone else tried DS2 from steam yet?