2H weapons vs 1H weapons + off hand [Warning: Math]

[Concillian]

The comparison is a little lopsided if you assume the person is playing a level 60 wizard with NO other intellect other than on their main hand and off-hand slots.

run again at 1000 base INT:
Plug into equation:
2H Hammer: ( 2007* 2.1 ) * ( 1 + ( 1101 / 100 ) ) = 50.6k min damage
1H Spear / Lich: ( 1509 * 2.1 ) * ( 1 + ( 1301 / 100 ) ) = 44.4k min damage
1H Spear/ Shield: ( 1344 * 2.1 ) * ( 1 + ( 1301 / 100 ) ) = 39.5k min damage

run again with 600 base INT:
2H Hammer: ( 2007* 2.1 ) * ( 1 + ( 701 / 100 ) ) = 33.8k min damage
1H Spear / Lich: ( 1509 * 2.1 ) * ( 1 + ( 901 / 100 ) ) = 31.7k min damage
1H Spear/ Shield: ( 1344 * 2.1 ) * ( 1 + ( 901 / 100 ) ) = 28.3k min damage

Like most stuff in the game, what's best depends on the rest of your gear. Since they multiply each other, higher base damage means higher INT has more value. The inverse is also true, as INT increases, so does the value of base damage. You can't give a definitive answer on this without knowing more about gearing than just what's in their hands.