I bought a 2400mAh 8.9Wh 3.7v battery from radio shack with these results:
I'm currently running SS9.2.1, overclocked to 1.5/245 w/ performance governor and I/O scheduler noop. With HEAVY use it will stay above 30% at 5:00 pm, I generally unplug it around 8 am.
If I turn the OC down to default of 800/245 it will normally stay above 50% by 8:00 at night. 90% of my phone use is between 8:30 and 5:00.
What drains mine the most if wifi tether.