A) Polls that asked both the "with Gore" and "without Gore" questions:

1.

FNOD, 5/15-16

With Gore:

Clinton: 35%
Obama: 20
Gore: 13
Edwards: 13
Richardson: 4

Clinton-Obama Margin: 15

Without Gore (with shifts in parentheses):

Clinton: 39% (+4)
Obama: 23 (+3)
Edwards: 15 (+2)
Richardson: 4 (0)

Clinton-Obama Margin: 16

Interesting "without Clinton" results:
Obama: 34 (+14)
Gore: 23 (+10)
Edwards: 16 (+3)
Richardson: 5 (+1)
(which shows that Obama and Gore have the best capacity to pull support from Hillary)

2.

Cook/RT, 5/11-13:

With Gore:

Clinton: 35%
Obama: 24
Gore: 10
Edwards: 11
Richardson: 2

Clinton-Obama Margin: 11

Without Gore (with shifts in parentheses):

Clinton: 40% (+5)
Obama: 25 (+1)
Edwards: 13 (+2)
Richardson: 2 (0)

Clinton-Obama Margin: 15

3.

CNN/OR 5/4-6
With Gore:

Clinton: 38%
Obama: 24
Gore: 12
Edwards: 12
Richardson: 5

Clinton-Obama Margin: 14

Without Gore (with shifts in parentheses):

Clinton: 41% (+3)
Obama: 27 (+3)
Edwards: 14 (+2)
Richardson: 6 (+1)

Clinton-Obama Margin: 14

4.

USA Today

With Gore:

Clinton: 38%
Obama: 23
Gore: 14
Edwards: 12
Richardson: 2

Clinton-Obama Margin: 15

Without Gore (with shifts in parentheses):

Clinton: 45% (+7)
Obama: 27 (+4)
Edwards: 14 (+2)
Richardson: 3 (+1)

Clinton-Obama Margin: 18

Averages:

With Gore:

Clinton: 36.5%
Obama: 22.75
Gore: 12.25
Edwards: 12
Richardson: 3.25

Clinton-Obama Margin: 13.75
Also, Obama+Gore = 35%

Without Gore (with shifts in parentheses):

Clinton: 41.25% (+4.75)
Obama: 25.5 (+2.75)
Edwards: 14 (+2)
Richardson: 3.75 (+0.5)

Clinton-Obama Margin: 15.75

B. Polls that asked or reported only the "without Gore" question:

1.

ARG, 5/9-12

Clinton: 39%
Obama: 22
Edwards: 19
Richardson: 2

Clinton-Obama Margin: 17

2.

Rasmussen, 5/07-10

Clinton: 35%
Obama: 33
Edwards: 14
Richardson: 3

Clinton-Obama Margin: 2

Average:

Clinton: 37%
Obama: 27.5
Edwards: 16.5
Richardson: 2.5

Clinton-Obama Margin: 9.5

C. Poll that asked or reported only "with Gore" question:

Gallup, 5/10-13

With Gore:

Clinton: 35%
Obama: 26
Gore: 16
Edwards: 12
Richardson: 2

Clinton-Obama Margin: 9

One notes that Obama's and Gore's number in this last poll add up to 42, 7 points more than Clinton.