One useful measure of nucleophilicity is the relative rate for a standard SN2 reaction:  MeBr in methanol at 25°C.  On this scale, we get the following comparison (compare Table 6-7):

Nucleophile
 krel
 log krel
 pKa of HX
Et3P
 520,000,000
 8.72
 8.7
HS-
 100,000,000
 8.00
 7.0
I-
 26,000,000
 7.42
 -10.7
CN-
 5,000,000
 6.70
 9.3
Et3N
 5,000,000
 6.7
 10.7
HO-
 1,000,000
 6
 14.74
CH3O-
 1,950,000
 6.29
 15
Br-
 617000
 5.79
 -7.7
NH3
 316000
 5.5
 9.25
(CH3)2S
 200000
 5.3
Cl-
 20000
 4.3
 -5.7
CH3CO2-
 20000
 4.3
 4.74
F-
 501
 2.7
 3.45
H2O
 1
 0
 -1.7
CH3OH
 1
 0
 -1.5