There's an island called Nias off Sumatra that's supposed to be good for surfing. I haven't been there but this site says the earthquake in 2005 that destroyed the nearby towns improved the surfing there.
Nias Sumatra Surf
I didn't go there because I heard the locals weren't as friendly as the ones on Pulau Weh. Pulau Weh fits your wishes except for the surf. I stayed at Yulia's about 20 mins down the jungle from Iboih. Very friendly, very basic indeed, shared mandi and squat toilets. People tend to stay there much longer than they intended, quite a few people stay for months.. Good snorkelling and seriously laid back and quiet there.
My favourite place in Indo so far is the Togean islands in central Sulawesi (again, more for snorkelling than surfing.) They're much more difficult and uncomfortable to get to than the islands off Sumatra though.