Well I am no where near the league you guys are in, but assuming there are a few budget travelers who are members here is my system for valuing miles: Basically I look for the cheapest internet or Flight Centre special (not including tax since you still have to pay the tax on top of the miles) and divide the price of the cheapest ticket I would spend money on by them amount of miles it would cost. These ones are all *A economy class ex-Australia awards for trips I have planned within the next few years:

Route award points cheapest fare tax point value
SQ-CAI 80,000 1835 110 0.022
NZ-RAR 20,000 778 218 0.038
SQ-JNB 100,000 1703 150 0.017
TG-KTM 50,000 1553 155 0.031
UA-LAX 60,000 1459 185 0.024
UA-MIA 60,000 2012 185 0.030
UA-SJU 60,000 2600 185 0.043
UA-TEG 60,000 2600 185 0.043
VG-RIO 80,000 2379 115 0.029

Sorry the spreadsheet pasted a bit funny and not all all the taxes have been updated since I did this a couple of months ago. As you can see, the best value is OZ-Caribbean or Central America, closely followed by the Pacific Islands, Central Asia and East Coast USA. The worst deal is to use miles to South Africa because reasonably priced SQ tickets are available for this route and they cost 100,000 miles. I think JNB and CPT, maybe NBO are the only places you can get to on SQ or TG from Australia-can't use LH via Europe as that bumps the price up. You have to be really organized to do this, not the sort who decides on the spur of the moment they want to go to Africa unless you have millions of miles which I don't and some of you guys do.