2,604,897 !!!! And I was about to kill Dracula for the 5th time, but couldn't switch over to the crossbow fast enough and he zapped me.
Tips:
1. Get the "Scoremaster" perk first. If you don't get it right away, restart. This will improve your overall score AND you will level up much faster. Make sure you also get get Bonus Finder and Telekenesis.
2. The crossbow usually kills Dracula in one shot.
3. You can actually pause the game and switch weapons (I didn't figure this out until recently, or that high score probably would have been higher.)
4. Use the environment to your advantage. I have my favorite spots
5. The BFG runs out of ammo fast. If your health can handle it, wait for a horde to gather around you and "don't shoot 'till you see the whites of their eyes"
Attached is the screen cap if you don't believe in my Van Helsing-like prowess.
Daniel (Spaniel)