Just noticed that there are people playing D2 here so i thought i'd share this (must have) mod.
Most obviously not for closed bnet play though.
It does work with Plugy and requires v1.12.
i'd not go over 1680x1050, the framerate might drop a lot and some glitches appear in certain areas.
1920x1200 D3D FSAA 4x just for the looks (it's a bit messy though)
Windowed Software Mode
You might have to tweak with GPU Scaling to get some res modes.