Configure within the app itself. i.e. for Whatsapp -> go into the app -> press menu, you should see options available for notifications.

You are sure its not the screen lock sound? See if its enable under "Sounds" in Settings.

I have tried Juice Defender and it helped a little on the battery, after 18 hrs, it still has about 45% - 50% (depending on what I do). On most times, I am on Whatsapp, moderate surfing on the Internet (FB included) and some live widgets enabled.

But users beware, you will have to tweak over a few days to see what suits you the best. Right now, the best I have gotten so far is a little over 24 hours before charging. Having said that, dont worry about the battery, just use the phone as it is intended. If you guys are so worried about battery life to the extend of no games, no internet, no this and that, isnt it better to get a RM99 Nokia phone that can last you for days before the next charge?

Use the phone with pleasure and dont let the battery icon restrict your experience of the phone. Afterall, we are always near a plug (wall or through USB) and if you are not, I would suggest you get a mobile charger like the Yoobao.