US Visa Question
 

For those folk with both C1/D and B1/B2 US visas issued for work purposes: are you able to travel for leisure purposes on the B1/B2, or do you still need the ESTA? The state.gov website isn't explicit. Cheers.

You do need the ESTA..and it is valid for 2 years !

Yes - the purpose of the B1/B2 is to enable you to visit without ESTA. There is some confusion over this but I have travelled many times to the US for holidays on a B1/B2. Never filled in an ESTA. If you ask the immigration officer if you should have done ESTA he will look at you like you are a headcase.
Not only that when I was issued the B1/B2, the consular officer specifically told me "no more ESTA for you".
Below link from the US Embassy in Athens (no idea why that one was the first result in google):
ESTA FAQs | Embassy of the United States Athens, Greece