Extra Battery

The Battery on my Droid Incredible 2 does not last long. A few phone calls, facebook, some internet and by the end of the day it needs to be recharged. I knew from other posts this may happen so I am not surprised. I wanted this phone anyway. My question is this. What extra battery should I buy for my phone. I know there is an extended life battery but have read it may not fit right and may be heavier. So I am thinking of just a regular battery for this phone but want to buy the right one.