One thing I found was that if you signed in to many accounts plugins like MSN + Yahoo + Skype + Gtalk + SIP etc. it drains the battery quick.

How many accounts plugins (haze etc.) do you have signed in?

I had the 5 mentioned above, my battery was draining quick, full charge only lasted 8 hours on medium use.

Since I disabled the accounts plugins except SIP when not needed, a full charge can last me a good 20+ hours now on medium usage.

I think the account plugins is the main cause.