I have upgraded my B&W to an ATi 7000 PCI card. This helped somewhat. Also, upgrading to 10.3 helped.
I still find that D2 is virtually unplayable on battle.net while running any version of 10 on my Cube (G3Force 2MX) or B&W. Heck, my quicksilver (GeForce 4) even has issues. Lots of dropped frames and bad lag. I am playing on a cable modem and on my LAN at work (T1).
My brothers oooold dell XPS-T450 (450mhz, 32mb tnt2, 512 RAM) running XP blows away my qicksilver in D2 under 10.
Now, if I drop down to 9 (not classic), then battle.net is usable. But I have no wish to continue to have 9 installed on my machines.
Oh well.