Your weapon definitely affects spell damage. I took off my wand and lost 49 min/40 max damage off Drain Life. The wand is 72 damage per attack, average. It's 60 DPS (for total auto-attack DPS of 86). The wand also has +5 INT, which complicates things somewhat. If I equip a different wand I gain 18 min/20 max over base spell damage (well, base with all my +INT equipment on).

Clearly I need to do some more research on how weapons affect spell damage, but I'm in the middle of doing the spreadsheet for how INT affects it, so that will have to wait. I'm going to do the +INT calculations naked so that weapons don't come into play.

Thank you Sky../ for the valuable data points. Pharcyde, are your numbers naked? Thanks for your information also.